I have no problem with this.
1st amendment protects the right of freedom of peaceful assembly. One of the reasons people assemble is for the conduct of business. In this case, rent of a property. In order to be Free to do something, you also need to be free to NOT do something.
If the landlord no longer wishes to rent to someone, they have that right. Granted there needs to be sufficient time to adjust living arrangements - a notice period. But the owner of a property gets to determine the how and why of the use of that property.
You get it!