Josh Sharpe created the WPPR system and operates the IFPA.  In a discussion in the facebook Club Pinball group, he has this to say:

If what you are saying is that a player shouldn’t have control over whether they are listed on the IFPA site or not, it’s a question we had to deal with back in 2006 when the rankings launched.

It’s interesting because a player choosing to compete in an event, is obviously allowing their name to be used at that event. We are simply using those results for our purposes, and how much power should a player have over letting us use the results of someone else’s event that they openly chose to compete in.

Ultimately we came to the decision that rather than forcing a player to have to be ranked because they chose to compete, we left the decision on them to remove themselves for whatever reasons they so choose.

Like Molly Atkinson pointed out, there are people that definitely take WPPR’s far too seriously that it ends up being a stress adder in their lives, versus an enjoyment adder. While I would like to think that a majority of the 28,000 players see WPPR as an indifferent/positive thing, there is definitely a group where it is a stressful thing. For those people if removing yourself will make your life better in any way, the IFPA wants to support that by not forcing you to remain as listed.