In many European countries, "anybody" can take money out of your account, but you can return a direct debit for up to 13 weeks in case of unauthorized payments, and for 8 weeks for no reason whatsoever (including you just feeling like spending the money on something else).

Practically, the bank allowing a merchant to submit direct debits takes on significant credit risk as a result, so they grant that permission pretty carefully, similarly to how card processing merchant accounts require some level of trust.