Comparing moves is one thing, calling a character a worse version of another is a totally different kettle of fish. Especially when the comparisons hold no water. I don't actually see that said about Falco much. Idk why you'd feel bad about him in that respect. Feeling bad about him because he's bad is fair enough but maining a bad character is different to maining an underrated one.
(For the record I don't actually think Falco is that bad, just wanted to get my point across)
Yes, but when it's things like saying Rosalina's Shooting Star Bit is a Falco laser, but better that just makes me feel sad. Functionally, yes it can be a Falco laser, but it's more like 64/Impact Blaster since the range is shorter and you fire once and deal with end lag and fire again while Falco can continually fire, but somewhat slowly.
So, you can compare say, Sheik and Greninja's Dtilt, but in the end they're still different tools that can be similar, but straight up saying Greninja's is better because he can get a Fair kill isn't the right way. Better is subjective since Sheik could Dtilt and string Fairs which would take longer to kill, but nonetheless, can kill or gimp.
A character can be undermined by having "worse versions" of several different characters' moves. That is really shallow way of looking at a character. What I'm getting at is that people have to look at the character as a whole; what their moves and attributes do for their game plan. It's why people cannot say Greninja is a worse Sheik. The only moves they "share" and can be somewhat compared is Uair and Up Smash. Everything else about them functions differently even if they function similarly like how their Bairs can be used to stage spike or combo, but tons if not everyone's Bair can stage spike and combo. Hell, Greninja's Bair might be more in line with Link's, but what does Link's Bair do to his game plan versus Greninja's? Even clones cannot be called a worse version of their original. Done right, you can't say Ryu and Ken or Marth and Roy are the same character and one of them is the worse character. Done wrong like Dark Pit and you end up with virtually the same character who is so minutely different, it doesn't even matter.