Earlier quoted context omitted.
But there is a good chance that these GET parameters are logged by the webserver. Even if these servers are very secure and strictly monitored, one bad employee can cause a lot of trouble.
Perhaps, but an employee in that position can steal credentials even without GET logs. This entire discussion is predicated on a contradictory assumption, that an employee would be corrupt enough to steal credentials from web server logs, but not corrupt enough to steal the same credentials from any other source (inc. database access). It is like letting a criminal into your home, then being concerned that they might…
(But part of what makes it OK to have more people with access to the logs is you don't put things like username/passwords for all of your customers in the logs.)