Why does facebook cancel all your pending friend request on 30 day block?

[Drizzy]

I only add people that I know. I don't abuse the facebook terms, send out spam, use a fake name, use a fake picture or anything else that is spam. Facebook keeps blocking me for sending friend request to people that I know, and one time my account got blocked for no reason. So why does facebook cancel all your pending request on a 30 day block?? Anyway that I can stop this?? It's really frustrating that some people didn't see the request yet.
I only had like 8 pending requests

[JJ]

You should probably reconsider who you send friend requests to, or make sure to tell them some other way that you want to add them and they should go accept it so as to avoid a large number of unaccepted requests.

[Terence]

I think some of your peoples which you have sent friend request has decline your friend request that is why you have blocked.

[SMN]

Either you would have send request to unknown people or the people who you sent the request has declined you request.