the airlines are obligated to ask these questions as they are fined significantly for visa breaches. You need to dot your I’s and cross your T’s when travelling.
The onus is always on the traveller however the airlines are severely penalised for the travellers error.
So they will and should scrutinise someone that becomes a red flag to them.
I have a Thai wife and having been raised to do everything for myself. I struggled with the amount of fuss she would make over me with respect to home duties.
When I stay with her family in Thailand the same thing happens. You are so right with respect to it being cultural.
I can say with sincere respect don’t question it or yourself. Just assimilate and enjoy. The fact that you are self sufficient is a quality that will serve you well in the Thai culture.
With respect to eating out. It is so much cheaper to do so and removes the need to cook in a very hot environment.