It's not pressuring you, it's just another method of warning you that the PC protection is about to expire. Stopping it can be as simple as purchasing another year or simply enabling auto-renewal via credit card. Not warning you that your protection is about to end would be far worse.
If you don't want to renew, then the nag screens serve to remind you that you need to get another protection application either online or purchased via boxed product from a store. I personally hope you get something, because it's those out there who don't that end up part of the bot nets that are constantly attacking everyone else's PC, including mine.
OneCareBear