"You can teach language through content" - language will always have/be "content", but this content is not always easy to classify e.g. it doesn't matter if "war" is mentioned in the context of "history" or "politics", just so long as it is mentioned somewhere (in an English class) as being an important word, and illustrated with examples showing important collocations etc. (In an English
language class, the context could even be something as "light-hearted" as 'war
movies').
"or content through language" - I think it would show a lack of respect for e.g. history as a discipline if dubious or shoddy language (and, in turn, probably wooly arguments or presentation of evidence) were considered "acceptable" (and to whom, in this case an English language specialist or a historian, if one weren't both!); more importantly, however, I am concerned about the effect/impact a CLIL approach has on the student's understanding of and subsequent potential performance in the underlying subject/content, especially if they have to at some point compete in their L1 with students who have studied the subject in the L1...but perhaps the whole point of CLIL is to send the students ever outwards into an increasingly English-speaking world, in which case, those students would be at an advantage over their compatriots - but not over native English-speakers, who will have obviously been held to much higher standards linguistically in all their subjects (and who will probably therefore also have reached somewhat higher standards in the subjects themselves!).
Ultimately, language
is content (and content is language), and there is no dichotomy, and therefore no problem when students learn subjects in their native language. The "obvious" advantage of CLIL (improving English) seems to me to be outweighed by the pressures it puts on students (and to some extent, their teachers, even native English-speaking ones); then, we should be asking ourselves exactly what level of English is achieved
in the subject.
That is, when the Guardian writer says, 'The main advantage of Clil seems to be the fact that the target language is acquired in a rather effortless way', a modifying 'of the subject' is noticeably absent between 'language' and 'acquired' there (at least, the language of the subject as it is expressed in or surrounded by good English).
What I suspect rather happens in your average CLIL course is that the students English "generally improves", but only in very non-specific, non-subject, general way (which is not tested outside of English language classes proper, if they actually exist in CLIL schools), whilst the linguistic performance in the subject is a half-baked mish-mash of learnerese that satisfies neither the teacher (especially native ones) or the students (who could obviously express themselves better in their L1) at a deep psychological level.
These sorts of linguistic problems might be overcome with careful planning and a linguistically principled selection of e.g. the English of "history" (the subject of history), but how often does that happen, really?* And would this have an impact (real, or even just perceived) on the "easiness" of English ('This specificity is making everything too difficult! Surely it shouldn't be so difficult to just "say" what you "mean"! We mustn't make the students come to hate English - we must (try not to patronize them and) applaud whatever lacklustre efforts they make in English for whatever complex subjects! Hopefully, we won't be expected to teach English Lit as part of our curriculum, then we'd really be in trouble!'

)? And what of the skill of writing in the L1 about whatever subject? Does that also just "take care of itself" too?

(=not happy fluffyhamster).
Probably things like CLIL are more the brainchilds of incompetent bureaucrats than linguists (and probably meagre linguists at that), and anyone who might express some reservations, along with some
serious suggestions for improving the programme
before it gets "up" and "running", could well be labelled a stick-in-the-mud or a no-can-do. But who, I would ask, is being the more realistic and practical here in the long run?
I suppose that ultimately, as a teacher, I would have no objection to CLIL if the materials were ambitious and aimed high (higher than the students would probably achieve, on average, and nearer to a native level of performance/"competence" - saying exactly what they mean/most often intended to mean), but would the students then have objections still - or even more objections?

Perhaps I should make things easier...but I am nobody's fool/b*tch/hamster etc, as an applied linguist or as e.g. a historian (not that I am that good at either discipline, but I do try to do my best, and try not to kid people when things really aren7t up to whatever task).
*I went for an interview recently for a job at a consortium of colleges that apparently helps Japanese students to study in the US, and was asked if I had ever taught "Writing" (the way it was said implied it started with a capital letter). I said no, that I had taught English, but was aware of what "writing" generally involved (I was thinking, but obviously didn't sassily say, 'Pen, paper and thoughts'). I also wanted to go on to say,
thoughts in Japanese (for/from/of the students) that need to somehow find expression in English...and felt like asking if they had heard of e.g. the University, and Academic Wordlist, but I managed to restrain myself and just had to presume that they wanted to know if I had done any "creative writing" kind of classes)...so I just said I obviously was aware of what "academic writing" involved (being a graduate), and that even so-called "conversation classes" (the bulk of my experience, "unfortunately") often involved reading in order to discuss, "process writing" etc, all without mentioning how much easier this was in English if you were a native speaker already in command of 99% of the vocabulary!!!
Interestingly, I met (=was forced to meet) one of the students who was going to study in the US. It took her at least ten seconds/several repetitions to understand the question (not from me), 'Where are you going to study?' (=tell the fluffyhamster visitor the name of the college you've been accepted at, at least). Maybe it was a cultural thing, a misunderstanding regarding the simplest of questioner expectations? Then again, this kind of lack of smooth communication seems to be quite frequent between "teachers" and "students".
