Well most of them knows why he does charity.
But also he doesn't do charity like from his own pocket all the time. Its that he runs an NGO where most celebs and other people gives funds and from there Salman utilizes it in charity.
Like in 2010 for TMK, Akshay and Katrina came on KBC and gave 50 Lacs winning amount to Being Human.
So like this many people donate to BH but at the end bhai ka naam aage ayega.
But its fine.