Protecting each other
Quite common here in Thailand. Udom knows too much about the happenings in thai aviation. If the DCA goes against him, he will uncover a lot of stuff that was kept secret over the last years which would affect the industry as a whole. That's why such agencies like the DCA usually go against the small fishs which have no influence or are too weak to react and fire back.
E.g. Chaisak Angkasuwan's son was made IT Manager at OX a couple of years back without having any clue about IT or the airline industry. One way of saying thank you to the director general for helping protect OX ... why do you think Chaisak Angkasuwan shuts up now? I mean he was the most outspoken 20 minutes after the crash already knowing that it was the wind and weather and nothing else.
The son later on moved to Nokair, but that's a different story.
Oh well ...