Since when? When do property rights trump the Constitution? Simply because you own property (which is ironic in this case because the stadium was built with public funds) does not give you cart blanche with regard to rules. Do you, as a property owner, have the right to detain someone against their will? Can a property owner forbid your religion? Or make you observe theirs?
Can I detain you against your will? No. That is an overt act which harms another person. That is not permitted on either private or public property (unless of course, you have attempted to harm me and I am detaining you while awaiting the police)..
Can I forbid you from practicing your religion on MY private property? Yes - to the extent that I can make you leave if I do not like your religion, or for any reason I choose, or for no reason at all.
Can I require you to observe my religious beliefs on MY private property? Yes - to the extant that I can make you leave if you refuse to observe my religious practices, or for any other reason I choose, or for no reason at all.
I probably won’t end up with very many friends, but that is not the issue.
The Constitution restricts the government, not individuals on their own property. The Constitution respects private property.
Actually, it should. If you are a property own want to ban clothing on your property, it’s your Right.
It’s also your Right to lose all your business and go away.
Caveat... If you OPEN your property as a business and invite the public in, then you should expect the public to come in under mutually agreeable terms.
The answer to all your questions is yes.
If you don't like the property owner's position vis-à-vis your religion, politics, etc. don't enter his property.
I don’t allow strangers in my house if they are armed. Yes, my rights to protect my family trump the Constitution.
The NFL has a lot of power when you consider that their stadiums are built by taxpayers, they are a big business and they are associated with media, so there is an iron triangle of power consisting of politics, business and media.