Hopefully the UN notices and takes some action. Vietnam was quick to stop discrimination against foreigners to protect 'the tourist image'. Vietnam was wise. Thailand is still stupid.
Reentry permit has there own special line at Immigration. Single and multiple entry are possible with there rules. Be nice. Smile. Have a good attitude and not a spoiled entitled western attitude.
If your in Chiang Mai or any other area of Thailand you can get a ED (self defense) self defense visa and pay the extra fee for a multiple entry visa. Not sure if that visa is good for 6 months, but one year for sure. Muay Thai training in most other areas is also a available. It's only an option. I had a 60 day tourist + 30 day extension. During this time I got a single use reentry permit to return to The Philippines. I did this twice. I also did the Vientiane visa run to get another 60 day tourist visa + 30 day extension. If I remember correctly I think a multiple reentry permit was possible when I got my reentry permit. Check Thailand immigration and Thai embassy/consulate for further updated information.
Learn Thai with an ED visa. A ministry of Education certified school can process the paperwork while you are in Korea. It is also common to process your ED visa while in Thailand. There is a. ED visa for self defense
In Chiang Mai and
Muay Thai ED visa too. There is teaching. Some schools teach Deutsche, but I think mostly in Bangkok. A degree will be needed. A few examples. This will all be a available at the proper time. Plan early. Research early. Tschuss