Welcome the world of text message SPAM! ;) Apple is doing something about this, but they cannot achieve this alone as it is not solely an issue that Apple can solve.
The following support articles is what Apple provides:
You may also need to review your online habits to see if anything you are doing is helping nefarious actors get your phone# / email address to send these SPAM messages to.
The bottom line is that we are all affected by these messages. You can certainly submit your concerns directly to Apple, here: Product Feedback - Apple
In addition, you should contact your cellular provider for help with this as a number of them offer services to help reduct them.