Couple of things:
1) the article never states that Nutt Bantadtan is a member of Pheu Thai, to be clear it also never states that he is a Democrat Party member. Those omissions are the fault of Thaiger Journalist Samantha Rose,
who, her profile says, is a "experienced real estate journalist"
2) Nutt Bantadtan has a conflict with Pheu Thai dating to 2012 when he was caught looking at nudies on his smart phone in Parliament and now he is telling Pheu Thai how to behave ethically and for the good of the country, however, he never advocates for his own Democrat Party to do the same.