some people ask questions just because they want their beliefs backed up, or an idea to get out of something, rather than genuine answers and being told they are wrong or foolish so they will react badly to being told that....
as for getting a thanks...its nice, but not compulsory to come back and thank everyone ...
i often come back and say thanks but not always. sometimes i thank in advance because you never know when people have finished answering so you would have to keep coming back and thanking after each response...i like to think people know i am grateful for them helping....as much as i believe they are grateful if i help them...
i dont mind not getting a thanks