I think we have the same powers, I haven't added many to my whitelist but I don't think we have a limit on the number we can add per month.
One problem is that I don't know if other members have whitelisted group requests or not. I also have to keep the list manually.
I tried to reply to people with your phrase like "You have been whitelisted now you can post freely" but I notice that some of them don't come back even though their email address is personal and they have a lot of activity.
There is another problem, which is that many wallets have a minimum (dust amount), so many users pay more than what is required of them.