Exploitation of rental laws

The legislature decided this because of the votes it wants to get from tenants... Is it moral for tenants to worry about a law that will allow them to pay less than they should for rent?

This is speculation that sounds unlikely to me. The voices of the landlords are equally important to him. In any case, if this is the legal situation, I see no obligation to act differently.

According to what you said, there is no reason for a person to refuse to enlist in the army if he exploits a loophole in the law or the law itself (as in the case of "his teaching is his art"), even though in doing so he pays a lower fee for the consideration he receives, right?

How did you come to this bizarre conclusion? Or maybe you were striving for it in the first place?
I wasn't talking about exploiting loopholes, but about acting according to a law that was enacted on the matter. The law that was enacted says that we don't follow a free market, but rather government regulation. What does this have to do with the obligation to enlist? When the legislator exempts you from enlistment, not as a perversion, there is indeed no obligation to enlist. But when the legislator does so arbitrarily for the sake of a narrow interest and causes others to be sacrificed for your sake, that's a different matter.

I'm trying to understand how one examines the morality of conduct within the framework of the law, that is, when exploiting a law (or enacting it in general) in a way that suits only my interest is immoral, and when there is no problem with it. Ostensibly, if renters can enact a law in their favor against the interest of the landlords, and taxi drivers can enact a law in their favor against the interest of the rest of the public, why can't Haredim enact a law in their favor against the interest of the rest?

I agree that sometimes there is a problem with this, but I have difficulty diagnosing the definition (if there is one).

I don't know how to give general definitions. There is common sense. When the legislator acted in bad faith for the benefit of a guild, it is easier to circumvent and overlap.