Earlier quoted context omitted.
I wonder if it's a really lazy and terrible attempt at accounting for how long the opt-out request would take. Let's imagine it has no way to know (because of cross-domain restrictions?) whether an opt-out request to a third-party succeeds - in which case it simply waits a reasonable amount of time for the request to complete. Of course, a reasonable time should be a handful of seconds, but I guess at least it makes…
It's entirely possible that it is the result of incompetence rather than malice. Either way, it strongly discourages users from rejecting cookies by wasting their time for 20-30 seconds every time. Whatever it's doing can simply be done in the background, it doesn't even require UI.
The whole point of the charade of "asking" is to get people to
1) Just say yes
2) Complain to their government about it