Why does Mega Man get praise but Mighty No. 9 get hate?

I own both Mega Man collections for PS4. I'm about 80% through the first collection and 30% through the 2nd. I don't like either but each game is pretty short and it's something to play for me to make me tired to go to sleep at night. Now I truly don't get why Mega Man games are praised so highly but Mighty No. 9 gets shit on. They are pretty identical to me and neither games are good. They both are beyond frustratingly difficult and not fun at all to justify the difficulty in the games. Both games have "instant death" moments that are just retarded in placement and is one the main reasons I hate the games. You can make progress in Mega Man and MN9 and then "instant death trap that's difficult to avoid" and the games rely on lives, so that makes it even more annoying.

So why is Mega Man so praised and Mighty No. 9 is so hated when in my eyes they play identical in design and unfair/non fun difficulty? Maybe people have nostalgia goggles on but I don't see why.