I'm not constitutionally required to let political campaigners onto my private property (my home), and I shouldn't be required to receive their text messages on my private property (my phone).
A lot of people agree with you but that’s not typically how it works IRL for USPS either. Generally if you keep trying to deny delivery of junk mail your letter carrier will tell you “you can’t just refuse mail”.
Although I think maybe you are supposed to be able to refuse it, just doesn’t work IRL? People are also supposed to be able to send the mail regardless.
I do think it’s a cost issue. Should cost the standard $0.60 stamp per each bulk mailer (bulk mailers are much cheaper.
Text messages and emails should also cost something reasonable which would dissuade abuse. Perhaps “accepting” a text (or at least not rejecting it) would waive/reimburse that fee so “good” texts could be free? Seems easy for this to be abused though by the body public when temporarily enraged against a corporation/small business.
https://faq.usps.com/s/article/Refuse-unwanted-mail-and-remo...
I agree with your other points. Stop the subsidies. I'm not sure why spam makes me so irrationally angry, but it does.
Commercial speech can be regulated provided certain requirements are met that are more widely applicable, a four part test is used. See Central Hudson Gas & Electric Corp. v. Public Service Commission. Also under Zauderer v. Office of Disciplinary Counsel the government can compel commercial speech, require advertisers to include factual disclaimers.
So laws like the CAN-SPAM act prohibit unsolicited commercial advertising via txt or email if certain requirements are not met.