Hard disagree.
1) They only made changes on the iOS app.
2) The last time they made sweeping changes to content policies it was at the behest of Apple (https://www.theverge.com/2018/12/13/18139940/tumblr-back-app...).
3) The changes they made seem utterly unrelated to a generic push to be more advertiser friendly.
Tags they have blocked include: "about", "about me", "arms", "beard", "donate", "hot", "long post", "me", "mine", "misc", "my face", "my gif", "my life", "queue", "queued", "repost", "self", "self reblog", "selfie", "snap", "stim toy", "submission", "suicide prevention", "tagged", "TMI", "Tony the Tiger", and a huge number of tags starting with the word user such as "userdave" or "userjane". (And then, yes, a ton of words with sex or drug connotations too, yes.)
Notice that a ton of these are actually meta tags relating to how people use Tumblr; "submission" is automatically added (by Tumblr!) for items submitted to a blog; "queued" is added (again, by Tumblr!) for posts queued to be automatically posted in the future; people often tag especially long posts with "long post", and so on. Then you get just weird things like "Tony the Tiger".
I'm not sure what exactly they're trying to do, but it seems very clear to me it's a half-baked attempt to stop getting kicked off the app store again. They've as much as said that this is an emergency fix and they will be rolling out something less broken when they can, but a general "let's be more advertiser friendly" push wouldn't be an emergency.