Doc knowing how to dance makes no sense

I hate when movies 'retcon' things just so they can make some gag happen or whatnot.

Did these people FORGET the only actual 'Back to the Future' movie?

Doc knowing how to dance COMPLETELY contradicts his reaction to the dance poster; Doc describes 'a dance' as 'rhytmic ceremonial ritual', for crying out loud!

Is that the vocabulary of a man who even knows what a dance IS? Let alone knowing HOW to dance, geez!

Doc suddenly knowing how to dance in this travesty of a thoughtless retcon sequel with injected romance (Who the heck thought it'd be a 'great idea' to make Doc 'fall in love' should jump out of a window) makes NO SENSE!

Not that almost anything does, when you consider how this character is a shadow of a cartoon version of what he was written as originally, not intelligent, not thoughtful, not meticulous, etc.. all the problems of this (and all of these) movie would SO EASILY be solved by sitting down for 10 seconds to just THINK.

Also, information affects the future, so as long as Marty tells the 1950s Doc not to build the darn time machine in the first place, all problems would, again, be solved (with paradoxes, of course, but that has been inevitable in these movies anyway).

Doc's answer to (wrong) Jennifer at the end is ALSO complete BS.

'What does that mean?' should be answered with 'It means this timeline's future was altered, so that event now never happens'.

What Doc ACTUALLY says makes no sense considering ALL THAT HAS HAPPENED IN THESE MOVIES, god damnit!

These are just couple of tiny reasons out of probably thousands why I do NOT consider these so-called sequels canon, or even worth watching at all. They're nothing but thoughtless cash-grabs - the 'first movie''s time travel has ENOUGH problems, these 'sequels' messed it up worse than the so-called 'The Terminator sequels' did..

I hate retcons, I hate injected romance, I hate thoughtlessness with these scripts, and I hate greedy cashgrabs, and I especially hate things that make absolutely no sense especially when they crap on what originally DID make sense..

Doc should NOT know how to dance, when he's a science-nerd that has never been to one, and does not know what a 'dance' even is!