I understand it's not a nice experience but I understand why they denied entry and it's totally reasonable and it probably wouldn't be different in any other country.
well I arrived a week ago Suvarnabhumi and the line was very long and it didn't seem like anybody got questioned at all. Didn't matter the nationality. Now it's not a great sample size but this was also my 3rd entry within a year with some more stamps from previous years and nobody asked anything. (even tho I have months of time in between them). Soms of this post here I really doubt it's the full story and I still think if you just a regular tourist you have nothing to fear even if you have like 2 stamps or more.