The issue here isn't whether or not there should be rules on the subway. And it isn't a question of should these people should have been kicked out or even cited for their behavior.
The issue is the insane overreaction and complete disconnect between the level of offense and the severity of the response.
Take for example the pregnant woman. I don't care how belligerent she got. The ONLY time such force against such a person is justified is when they are an immediate threat to the life or limb of another. And a bad attitude falls several orders of magnitude short of that threshold. Imagine the response to anyone else but the 'King's men' committing such an assault!
And cuffing a 12 year old...?
Scream a string of obscenities at me in public for no rational reason, and I will kill you on the spot. People who act like that are mentally unbalanced, and I would perceive an imminent threat to my life. IMNHO, the cop acted with a degree of restraint.
And cuffing a 12 year old...?
Again, in both cases, the arrestee was in an advanced case of BPOC Syndrome.