I'd say they're similar but not similar.
I don't think it's right to say Marcus doesn't respect the shirt or love the club, because I'd assume he very much does. And for the most part, he is professional.
I think Marcus' problem is more psychological than anything else, and it really does look like he doesn't at all enjoy playing football.
That's not an excuse for him, obviously, and it looks like his time is up. But I don't see any similarity between Micah, who was partying till the early morning on the day of a CL match, and Rashford, who has never hardly ever been said to be unprofessional.
Micah Richards is just a monumental idiot who was arguing a point that even he didn't understand what he was trying to say.
I think you're misunderstanding me
a- I don't think that Marcus is a money grabber, a virus etc. What I am saying is that both (Richards and Rashford) had faced similar accusations by the fans
b- If you follow Micah Richards you'll know that he's got an inflated view of himself. At one point he even rated himself as better then Gary Neville to the point that things got so ridiculous that Keane had to intervene.
So you have a former player who like Marcus was a very talented player in his youth, who somehow fizzled away as he grew older and who had faced similar accusations to Rashford from fans. Sure Richards had never reached the heights of Marcus but that's something that Richards doesn't even accept. When you take all of that into account then you can finally understand why Richards defend Rashford so much. He sees himself in Marcus.
Regarding Marcus 'downfall' so to speak I think its a mix of things
a- we didn't manage him correctly as a kid. He wasn't given the soft introduction to first team football that the likes of Scholes, Beckham and co were given. Being effective on the pitch is only part of a player's maturity to first team. Players need to be physically and mentally mature as well. Else you risk what I described better in b, c and d.
b- Marcus doesn't have the thick skin needed to be a Manchester United player. That's a trait many players are either born with (ex Keane) or are coached in. Unfortunately we lack the leaders to do so
c- Marcus wasn't properly coached. His style is very predictable and rely on pace which leads us to D
d- Marcus was run to the ground at one point of his career. That affected his pace. He's not a slow player but he seem to have lost some of his explosiveness.
e- He was given a contract that he simply doesn't deserve. Some people think that undeserved salaries only hit the club. Well it hit the player as well. I am pretty sure that Rashford wouldn't be under such scrutiny if he was paid 120k a week instead being at par with the likes of Salah.