I feel sacking customers got really popular during Covid and continued after.

Many phone systems have a thinly veiled threat about zero tolerance policies, to treat staff with respect, and in the case of certain government agencies here in the UK, that they will refer cases to the police. The same is repeated on written posters in eg doctors and dentist offices

Just a coincidence I’m sure but I find employees (especially on the phone) even more condescending and unhelpful these days

See “amazon disabled account after delivery driver misheard automated message from security system” incident.

Earlier, banks used to warn customers at least once for any disrespect towards employees. Now, expect big banks and financial institutions to close accounts without any warning, unless you are a wealthy client. Charles Schwab and Chase do that.