reason is ik where the previous person got there coins from and yes i do care about privacy at times since i do transactions with other people from forums all the time.
If you are always receiving deposits from people and you do not know where their coins are coming from and whether their wallet is compatible to yours, why not provide them all the options? Give them three addresses then, one bech32, one p2sh, and one legacy. In which case, they could freely choose their preferred address.