mrz - you say that Mr Rosen isn't speaking for all teachers - I don't think he's trying to. He's trying to speak for children, not teachers, as although teachers will obviously be affected by the changes, his - and my - primary interest is the children, and the impact of these changes on them.
I'm guessing you don't have a primary-school aged child yourself right now, because if you did, you'd better understand the impact these changes are having on them. I couldn't really care less if every teacher in England thought the changes were wonderful - although they clearly don't, as you can see here:
www.tes.com/news/school-news/breaking-views/dear-secondary-colleagues-when-i-send-my-teacher-assessment
www.tes.com/news/school-news/breaking-news/ticking-198-boxes-new-primary-assessments-means-days-extra-work
www.tes.com/news/school-news/breaking-views/ministers-must-remember-while-potential-every-child-indeed-limitless
www.tes.com/news/school-news/breaking-views/i-am-part-teaching-crisis-these-are-reasons-why-i-feel-i-have-no
www.theguardian.com/education/2016/mar/11/primary-school-spelling-tests-dyslexic-pupils-teachers
Your statement that Michael Rosen speaks only for himself would be more convincing, if it were not for the comments on the articles that he posts, such as here:
www.theguardian.com/education/2016/mar/01/nicky-morgan-testing-primary-assessments
or here: www.theguardian.com/education/2015/nov/03/morgan-grammar-test-right-answer-spag-english-spelling-punctuation-grammar
By the way, I assume you personally work in all 25,000 primary schools in the UK, seeing as how you claim to have a greater knowledge of what goes on in them than Mr Rosen does, who has 'only' visited a few hundred of them? Maybe you could enlighten me about when you last visited my son's school? It would have been great to meet and have a chat...
Your critiques are themselves so full of errors I barely know where to start. Your comment about grammar teaching not having changed 'for decades' is mystifying - please link to where primary-aged children were required to know about 'fronted adverbials' or the difference between 'subordinating and co-ordinating conjunctions' prior to this year? I certainly didn't learn this at my primary in the 70s (an excellent primary) and nor did my older two dcs, the younger of whom was in the first year to sit the SPaG test.
When you say "he says it isn't grammar but it is grammar" - what on earth are you referring to? He doesn't say it isn't grammar, he says the grammar presented in the tests is both (on occasion) inaccurate, frequently imprecise and largely pointless. He's not saying fronted adverbials, say, don't exist as grammatical terms, as you appear to be claiming, but rather querying why on earth we should want our 10 or 111-year-old children to be tested and labelled as 'meeting the expected standard for their age' or 'failing to meet the expected standard for their age' on something so fundamentally irrelevant and unnecessary. I could pass or fail a child on whether or not they could translate a recipe from Korean into Bantu, and that would no doubt be both 'real' and 'difficult' but that would not make it a sensible test or a good measure of my child's ability in anything meaningful or anything other than a complete waste of their precious time.
The point he is making is that the content of these exams is arbitrary and capricious. (And occasionally downright wrong.) The tests are invalid because the (very important) inferences that are about to be drawn from them cannot reasonably be drawn (that is the definition of validity - really hope you know this!). Children are about to be judged and in some cases life chances limited based on a test that is a nonsense, a spurious, back-of-the-envelope fiction.
If you don't care about that, then you should not be allowed in any classroom or near children anywhere, and I couldn't care how many years you have in the classroom. I'm just thankful you are nowhere near my child and I pity the poor sods you do teach.