Your too nice Mera and they are playing on your niceness .
The same thing happened with me in a different situation at a work place where there was a very odd chap who if you let him preached and quoted the bible , A LOT .
I also didn't want to be rude and would let him have his little chats but they gathered frequency and depth . People were noticing that I was spending time listening to him and making comments such as "are you converted yet " .
I found it hard to have to say to him please , no more religious talk but I had too . The poor guy couldn't understand my sudden change of heart so in a way I lead him on , I patronized him for the sake of not being rude which done none of us any good .