TL;DR, Microsoft have decided that end users should be able to buy whatever addon Power platform software they want for 365 without their IT departments permission or ability to block it.
The uservote requesting the ability to block this feature has hit over 3k votes in less than a week, currently putting it as the 6th most requested feature for Office 365 Admin... Considering that all the other requests with more votes are several years old you'd like to think they will get the message.