So far as I can see most of the agents cited seem American, or at least work for American agencies. Whether that makes a difference or not when compared to UK (or other) agents I couldn't say but it should probably be taken into consideration.
Also, as has been mentioned above, agents work with different genres so should be aware of the various genre conventions. The linked article in the OP doesn't say whether the agents whinging about prologue are primarily working in the crime genre, or literary, or chick-lit, or fantasy etc etc. That makes (literally) a world of difference in some cases.
I really think that authors should take want agents say with a pinch of salt. Yes, they are the (self-described) gatekeepers of the industry, but that doesn't necessarily mean that they're always as rigid as these articles sometimes imply. Often they will pick something up just because they like it. I also think that, more relevant, agents don't always actually believe the advice they give out, though I suspect they'd never admit to this publicly. What agents are looking for is a business relationship, and so giving people a fairly rigid set of guidelines is a good barometer to gauge whether or not someone is capable of conducting themselves professionally.
I broadly agree with Chrisp's analysis that, at first glance, it looks as though agents are trying to squeeze all novels into this cookie-cutter mould, but I once saw the slush pile of a major agent, and trust me, it looked obscene. They need some method of filtration, and once you're "in" you do seem to get a lot more say and flexibility about what you can do to shape your novel.