People are fundamentally misunderstanding a lot about this card and why it may or may not be something to worry about.
On one hand you have people saying "omg free value, axe it!" and they're wrong.
On the other hand you have people saying "lol dies to removal, 6 mana do nothing, ect" and they're also wrong.
If you think you can judge cards solely in a vacuum, then you're missing the plot. In a vacuum - Winota is a bad card as it a 4 mana dude who does nothing unless you have other things on the battlefield. Winota also has zero protection and dies to removal just as easily as MM. However we all can understand that Winota is a broken card because of the sheer value the card can give that snowballs out of control. You don't see Winota at anything lower than high B3 games for a reason (if you do, the player is trying to pubstomp you) and it's because the sheer value the card presents overshadow's even the game changer's list at times. MM is a card that requires other pieces to push it, and anyone playing MM is also likely playing those pieces as well. I am not saying MM is like Winota entirely, I'm saying that you can't judge MM like any old creature in magic that can only be in the 99. You also cannot ignore that he does provide progressively more and more value the longer the game goes, which is what happens a lot at bracket 2-3 games. The minute someone lands a piece that allows them to draw a card on each opponents turn you've effectively turned the game into "every turn is my turn".
Let's flip the script: MM is colorless and that is a hinderance more than a benefit. Busted legendary creatures in commander are more often judged by their power in the zone, and much less the 99 (eg Erayo, Golos, Leovold, ect). MM's deck HAS to be colorless and colorless has much less resources to work with to draw cards on each opponents turn with little upfront investment. There are some, but they are usually symmetrical (temple bell, GRS, ect) and can provide your opponents with other benefits as well. This is a massive hinderance to MM's overall power as a card because the higher value it can provide will be hard to unlock without more investment and requires your opponents to not use that benefit you're likely providing to remove your game piece. MM is much like the other 6 mana colorless commander: Zhulodok. Does nothing itself but provides really good value with other cards. You don't see Zhulodok at bracket 2 games very often because the type of deck Zhulodok pilots is often too oppressive for bracket 2 games. Someone playing a tuned Zhulodok deck playing against what is effectively the precon tier is someone trying to get easy wins (which is kind of funny considering Zhulodok helmed a precon and the OG list is actually pretty fine for bracket 2, all things considered).
Overall, Molecule Man is pretty good card. It'll shine much better in the 99 than in the command zone alongside cards that allow you to draw on each opponents turn with little investment. He's a very good card in bracket 2, completely fine if not a little mid in bracket 3, and bad in bracket 4 and 5.
Everyone is clowning on casual’s takes about Molecule Man, and missing the point.
The card isn’t broken or ban worthy, is it IS going to make Bracket 2-3 games miserable if the table isn’t prepared for it.
I think that’s what people are trying to articulate.