What we learn in chapter 3 is that whenever MC makes contact with a ghost then the ghosts regret comes out which she finds quite scary
Now she is in a big dilemma because she now has to deal with a ghost that is scary when she ignores it, what to do what to do.
I don't think it meant that the ghosts' regrets come out per se, I think Michi said that once the ghosts realize she can see them (aka they have contact with the world of the living through her), they get aggressive. Maybe it's their desperation coming out. They suddenly wake up and no one seems to be able to see them, they might be aware that they died but not why they are still in this world, so when they notice someone for the first time since they died is capable of interacting with them, they chase after her. And as it seems negative emotions can be a powerful trigger for these ghosts to turn less human (be it in their appearance, like the little girl at the beginning of Ch.3, be it in their behavior like how Aizawa acted more like an evil spirit/fiend than a girl)
In Aizawa's case I think Michi will slowly start to notice that ignoring also doesn't solve the issue. As the story showed us so far, many of the ghosts MC could see would not hang around her for long. They either just disappear after she ignored them — so they thought she couldn't see them — or lashing out when she interacted with them, which would make her flee and most likely make the ghost loose track of her to never see her again. Aizawa-san seems to be the first case in which she's been "interacting" with a ghost for so long, since the deceased is haunting the classroom, a place MC can't really run away from.
Either Michi is truly the source of Honami's "outbursts" (like the script just exploding here on Ch.5) or not we have yet to see, because if that is the case and she feels she is the reason why people's safety are in danger because the ghost of her classmate has been there for too long, she'll have to act and hope the same thing she's always experienced happens: Aizawa's ghost turns scary/less human and the issue somehow solves itself. A possibility raised by Michi could be that after seeing she can't convince the only human who can see her to help her with whatever it is that she needs, the ghost will leave the classroom for good — something that clearly won't happen in this case.
We still don't know what happens to the ghosts after they try to "attack" Michi and she runs, so I am just assuming what's been going on so far is that she would run for her life and never be found by them again.