You are telling is the one side story but the real problem is that they have restricted to sell to unknown users due to lot of users without id verification open the account and unnecessary they go for buying from users and wanted to scam them by saying they have paid and give you fake payment slip. That is why the bitcoin sellers in localbitcoin are asking your id cards so that they can get saved by this unwanted problems. Even the users who buy bitcoin can also use illegal accounts which got hacked. So to avoid this all problems the seller ask the id proof from the buyer so that he can be safe in future for any problem.
He might expecting well here, which is should not, yes we may expect something and be positive always, but we must also embrace the consequence that bitcoin is not a machine which will just give a profit at all time.