He's talked about it multiple times, Joy. You can actually go back through the threads and look for his responses. Just click on his profile and look for threads about spam, and you'll find his take on it. Here's a link to his profile: https://community.ricksteves.com/users/1000
ETA: for what it's worth, I don't think there's a real problem with one response that says "reported to Webmaster" or something similar. It's the multiple responses with the jokes and the comments that make the spammer realize that people are paying attention to this spam, remarking on it, and therefore they come back with even more spam later.
And with regards to leaving a reply in a post, as someone pointed out above, there's a risk of someone clicking on a link that could take you to a spammy website so it's good to give a warning. I do monitor the posts and keep them open so that I can go back and check later to see if the spam has been removed and if my post has been removed. If it hasn't, and the spam is gone, then I delete it myself, as there's no more need for it.
In fact, sometimes I will find posts made by other members here that remark on a spam post above them. The spam post is gone, but the members' post is still there. So I will just report it, and in the comment section, say "spam post gone-pls delete" or something like that. Then the tech team can delete the post that is no longer needed.