I certainly hope it's challenged in court. It certainly doesn't look like it has gone through a sufficient number of legal channels. Where are the studies? Where is the unbiased research? All we seem to have is "many have complained about the smell" and some irresponsible parent got their toddler extremely stoned. How about some science? How about looking at other countries that have legalized it and see how they overcame hurdles? How about showing the public how much tax income has been generated? Also, if there are 18,000 shops but only a small percentage are licensed, how about going after them and thus generating more tax. I see no serious downside to having cannabis legal, taxed, and regulated.
[begin rant] At every level this is causing problems. Thousands of Thais have benefited from the surge in popularity when it was decriminalized. Now, for zero solid evidence that it's causing harm to society or the health of the participants, it's back to being scary. The government betrayed farmers, entrepreneurs, workers from all sort of associated businesses, etc.
Plus, every time I heard about it affecting the 'image of Thailand' I can't help but think about how much damage alcohol ACTUALLY does to society, health, and safety. Alas, they don't seem consistent in their concern over safety, health, or society when alcohol is involved. [end rant]