Depends on what state and what you mean by "reporting them." Many states prohibit a landlord from "retaliatory eviction" of tenants who report violations to the authorities. There are often statutes that raise a "presumption of retaliation" and allow immediate dismissal an eviction case if it is filed within 6 months of an agency taking action against a landlord, acting upon a valid complaint by a tenant.

If it's just a tenant complaining to the landlord, the landlord can be notified immediately of the intent to evict, thus nipping it in the bud, rather than waiting for the tenants to file an official complaint...

This happened in an apartment downstairs from me: the tenants complained to the landlord who did nothing. The tenants THEN complained to the city, which fined the landlord, made them perform the $60,000-worth of de-leading, plumbing and heating upgrades to that apartment, and prohibited the landlord from evicting them for at least 6 months. We all eventually moved out, leaving the landlord with an expensive mistake.

They can evict you for any reason they want if it's a month to month. All they have to do is give you a 30 day notice. The reason doesn't matter.

While these things vary by state, typically the landlord cannot retaliate against you for things like this. That said, if you are month to month and the landlord doesn't tell you why you're being asked to leave then you're out of luck unless you can come up with some real evidence.

Yes. If you don't like it...move.

YES. Stop asking over and over. If you have no lease, they can kick you out with proper notice for any reason at all, or no reason at all. PERIOD.