Because they have damage reactions, especially weakness reactions.
And that's exactly my point. It would be far more thematically appropriate for all of them to have semi-random reactive AI in-game rather than strict patterns, and especially not such pathetic reactions that they can really on damage you until you get in the first hit, after which it is an exercise in tedium to kill them. If anything they should fight HARDER if you hit them with a weakness, such as anyone who has a half-dead power up getting it immediately. Guys who lose parts & attack options like Launch Octopus or Magna Centipede should switch it up to either a more aggressive AI or more of an elusive keep-away style... anything to show they actually recognize the threat they face, you know? Facing a reploid with the right weakness should reward the player with a more exciting battle while taking huge chunks of life off at a time, not hand them a cheap victory that feels like a consolation prize.
Magma Dragoon is perhaps the most pathetic example... basically Akuma who also has Sagat's low fireball for some reason, this guy is usually such a spastic threat that the dev team thought it was a good idea to let players bring a ride armor into the arena. But oh, one hit from Double Cyclone and he can't do anything but jump from one side of the screen to the other, never leaving your firing line to keep him locked down forever without a single counterattack. Congratulations on your 'victory', X. You get EFFORTLESS TEDIUM.
But couldn't it be even theoretically possible for a reploid to be infected with the Maverick virus and never commit a crime?
Yes it absolutely should, but the actions of some are seen as justification to hunt down anyone infected on the chance they might also go on a rampage, thus providing motivation for some to act against society that wasn't actually there before. The glaring hypocrisy of the maverick hunters honestly should be enough to drive even non-infected reploids to rebel against their tyrannical ways, which of course will also get them labeled mavericks. Hooray for fascism.
And just where exactly do humans stand on all of this? How were reploids treated prior and during these events? Where do they stand on the several attempts of reploids to create their own culture? Why is there not even one example of a human agency getting involved in the global crisis? When you think about it in these terms it seems more and more like a slave revolt with the maverick hunters as collaborator uncle toms. Hell, it's possible the humans actually largely side WITH the mavericks and the MHs are seen as "big brother" fanatics drunk on their own authority of force and accountable to no one while led by the very two beings responsible for the situation in the first place.
Actually that raises another rather biting question: if the virus causes mavericks and it originally comes from Zero, why was there an organization of maverick hunters for Sigma to lead in existence prior to his discovery?