In case you are confused about the last one: you may think it is referring to MLP's FiM reboot, which was created in the 2010's, not 2000's, but they are actually referring to the likes of Pucca and other animations from that time, which are indeed Canadian and made in flash.

And yes, people were complaining about these during that time, too.

I am not entirely sure what is this fixation about identifying animation trends and techniques and pretending that their use is automatically a bad thing, even though the same has been done for literal decades. It is like people learn about an art style by name and that somehow entitles them to using it as a pejorative, as if shows like Steven Universe, Gravity Falls and Star VS the Forces of Evil were not definitive proof of the contrary.

I suppose that is what happens when people romanticize the idea of art drawing too much: if your art does not look impossibly original according to some arbirtrary scale of originality created 10 minutes ago, your art is bad, your show is bad and you should feel bad.

…I am still not hopeful of this Thundercats reboot, though, not because of the art, but because CN has been nothing but disappointment lately.

The point OP is trying to make is every decade has certain animation trends that are most common in the mainstream, and yes anime influence was quite common at the time. Pan Pizza recently dragged up some old forum comments people made on animation boards of the time that complained about how shows like Teen Titans, Ben 10, Transformers Animated, Code Lyoko, Totally Spies, and more were copying so many elements from anime that "Western animation is losing its identity, soon everything will be weaboo crap" or something like that.