Yay for having 2 versions of react, a bit of jQuery, 2 versions of Vue enqued by 5 plugins resulting in 10 requests, some other libraries loaded on the Post edit screen. This is not a good thing.

Within Gutenberg itself, any library your plugin uses will be loaded, but these libraries are all quite small – Preact is 3KB, Vue is 20KB, React is 35KB, Polymer is also around 35KB. Even assuming a site has plugins installed that create blocks with every possible framework, this is still a fairly small addition. Of course, these files are rarely downloaded, as your browser is probably already caching a copy of them.

On top of that, the Gutenberg team are investigating loading Gutenblock components asynchronously, to ensure that sites with lots of blocks, or particularly heavy blocks, can get the same editing experience as everyone else.

Of course, the better solution is to reduce the number of frameworks being used – this seems like an area where plugin development best practices will evolve to make use of the latest version of frameworks, and potentially from a common source, for more comprehensive caching.

You saying that this is good to me just sounds like you can’t defend the decision to go with React given the support for Vue so you try to supplicate critics by not taking a stand. This is even worse than going with pure React.

Vue was far from the only framework being advocated for, though many of the discussions have been framed as a "Vue vs React" thing. Far from being that, I think the clearest thing to come from these discussions is that people want to be able to develop against the framework they're most comfortable with, and I agree with that they should be able to. Core doesn't need to force this decision upon them.