According to landlord and tenant laws discriminating against a felon is considered illegal.
Which means that landlords are not legally able to discriminate against a felon who is applying to rent an apartment or house.
However there's always other apartments and homes to rent so I personally think a landlord has the right to rent or not rent to whoever they please.
Although the law begs to differ a landlord should have the right to rent to whoever they want too and should also be allowed to refuse to rent to certain people.
No one is forcing a tenant to rent a place so they can always go to a different place to rent and I would say it's a good idea for some landlords to not rent to felons because although some people can change it would still be not very safe feeling if I knew a felon or ex felon was living next to me.
If the felon has a history of drugs and drug trafficking then yes the landlord can discriminate against those people.