Google is protecting the quality of the UX for its product (web search). If you choose to a "technical solution" that makes search results bait-and-switch for mobile users, it treats your search results as less-likely-to-be-valuable-to-users, because they are.
> This is bad news for consumers
Its good news for mobile users of Google search. What consumers are you talking about, and how is it "bad news" for them?
> and web masters
Its bad news for bad web masters, sure.
> and they're dressing it up as if it's the developers fault when a separate site is a perfectly reasonable solution.
They aren't penalizing developers for using a separate mobile site, they are penalizing you for redirecting all links to the regular site to the homepage of the mobile-specific site. Redirecting from specific pages on the regular site to the specific, relevant content on the mobile site is not penalized.
> It's not Google's job to dictate our solutions.
No, its Google's job to assure that their search engine provides relevant, quality results to their users, which is why they penalize sites that do things which would result in users not get relevant, quality results.
This is social engineering that I like. I hate people serving up weird broken content because they've detected a browser window size.
But it's not even that. Google have discovered some sites return a useful hit, but when the mobile user clicks that link they are re-directed to a non-useful page. That makes Google results less useful for those users. Google is thus only asking you to make those hits as useful as they appear to be. That's perfectly acceptable. It's not different to down-grading people who stuff a bunch of keywords at the end of the page - those are not useful to anyone and thus Google doesn't give them high rating.
If any Googler's (or DDGers or etc) are reading I'd love it if search engines gave me an option to search for "Valid HTML and valid CSS only".
I think that would be irrelevant. But I don't agree that's what happens. They produce an alternative version of the site and additional code, that makes it worse than what they had to begin with. It makes the site a worse place to end up on from search, so it's ranking got nerfed. As much as I sometimes disagree with changes to google algorithms and their position, I think this change is both technically and socially correct. Everyone who didn't spend time and money making their website worse - wins.
This is bad news for consumers and web masters alike and they're dressing it up as if it's the developers fault when a separate site is a perfectly reasonable solution.
That some sites are still struggling to deliver a good mobile solution is irrelevant and a red herring.
It's not Google's job to dictate our solutions. Do you not remember their rubbish hashbang solution?