That's my exactly my thoughts too . They have realised how much money they could be making if all those visa exempt entries became paid for by visa fees . It's not they don't want people to visit they just want to make more money .
Anonymous participant I would say , that is the reason you were denied then . Regarding the email there is probably something lost in translation between being denied and blacklisted . Try for a multi entry tourist visa as the embassy suggests and see what happens , it's cheaper than a DTV .
I assume you are talking about trying to re-enter straight away after your first 60+30 visa exempt entry has expired . There is less chance of you getting denied entry if you stay out of Thailand for a few months ?