I agree with you, OP.  There was a time in 2017 when hilariousandco actually started a thread in Meta about adding some new members to DT2 via his inclusion(s).  It was a big enough deal that he wanted to solicit the opinions of the community, and I do think that any new DT members ought to be made aware of that fact at the very least. 

I get that Theymos wants to have a fairly broad DT pool, but there are still some do's and don'ts that members should abide by.  I'm not sure how many members end up on DT2 without knowing about it, but OP is one example of that.  It probably isn't a huge issue, but OP should have been made aware that he was going to end up on DT.