I'm not comfortable sending copies of my passport/id to exchanges, but I would be comfortable just giving my name, address, etc like I do when creating a stocks trading account.
You send them your social security number when signing up for a stock trading account as it is required by law from the SEC. Giving someone your social is much more serious than these big exchanges asking for an ID or Passport.
SSN is serious data, and SEC mandated it to get hold of all Cryptocurrency users of USA, but the same is not true for the rest of the world. In my county, I can easily trade bitcoin without providing any government ID but in small amounts which goes according to my previous transaction history.
For example, If my usual transaction volume is 20k in a month, I can exchange bitcoins for a smaller amount like 15k every month. It won't raise any alarm. But if I suddenly exchange a bigger amount like 60-70k in one go, my bank will ask for an explanation and they might freeze my account if suitable explanation can't be provided.
I recommend to use Localbitcoins website. I am not sure about USA and other countries, but in my county, there are a lot of buyers available who won't ask for ID verification. The only requirement is bank account number and you good to go. But make sure not to exchange in big amounts.