It probably falls under the ‘not illegal’ category. They got the number somehow, and I would bet it’s from some stupid agreement that lets a company sell his number and whoever buys it is allowed to send messages to it.

It’s also hard to get harassment charges for these, since realistically it is hard to contact the assholes and tell them to stop sending messages, which is required for most cases. There’s also the issue that harassment needs to be a repeated thing (and usually after being told to stop) from the same source/conspiracy. If you could prove all of these different messages were from the exact same organization, or that each entity sending the messages had collaborated, you could possibly get a judge to agree that harassment took place. Then, of course, your issue becomes the question of who did the harassment. If the judge/jury believes that it was a particular individual at the corporation, maybe that person could be prosecuted, but if they only will say that it was the entity, like a PAC or LLC or inc. or whatever, you’re boned. No one holds business/political entities accountable.

All that to say… those of us who get these messages are boned, with little legal recourse. I just block the numbers and delete. It seems like it works, because I haven’t gotten any messages like OP did for the last year or so. They must reuse numbers to send texts.