From observation, Thai citizens are unhappy about it but generally accept it as part of life.
They are embarrassed by it but not enough to bring about a drastic change to the people around them or society. The majority of Thai people won't go up to a fellow Thai person and publicly berate them for littering. They also have not approved of laws that would fine people excessively for littering.
While Thai citizens may say that they don't like garbage or littering, they're also not doing anything active to change it either. It's part of the Thai "sabai sabai" culture which is considered very laid-back.
Contrast this to the recent political protests in which Thai citizens were incensed enough to actually take action and we can see that the issue isn't pressing enough for them to take action.
Written 10 Mar ·