Scientific knowledge is contingent, things should be presented as our best theories to fit to the known evidence.
When the evidence changes, so should the theories.
I am only ever critical of the process when the above does not happen, or when people refuse to look for new evidence when it's reasonable for them to do so.
That's certainly true. In the case of dinosaurs though, there was probably a lot of evidence going back a long way that might have led someone to reasonably conclude "This is a fossil of a turkey, not a lizard." (Obviously a lot more than just looking at a fossil but, as I understand it, the rethinking of dinosaurs wasn't driven solely by new evidence.)
I also read the original comment more in the vein of: "Just because something thee the scientific consensus today, doesn't make it necessarily correct." (Though of course some things are more unlikely than others to radically change.)
Even today you'll have detailed descriptions and explanations of some dinosaur, and it turns out we have half of one bone and part of a head, and that's basically it.
Without spending years studying the stuff, it's really hard to figure out what is "this is absolutely known" (as in, we have a full fossil found in one location and in one piece) and what is "this is our current educated best guess".
When the evidence changes, so should the theories.
I am only ever critical of the process when the above does not happen, or when people refuse to look for new evidence when it's reasonable for them to do so.