The parasite system was crippled during Elements Chess and killed by War #4. Until the system is re-evaluated and something can be created that will not include exceptions for certain members or situations it will not be enforced.
No reason to put this system on hold.
The thing is that there has to be at least two "tiers" or whatever to these Parasites so that being inactive in a small event with 16-32 players, will not ban you from the ultimate PvP event, War. Anything can happen, so even though a player is usually very active, he or she might have to skip one small event. Is that enough to be banned from War that happens only a couple of times a year? No. If we did it like that, it would be an unfair and vindictive system that is not really the goal here.
Now if that person quits War (or disrupts it), then it makes sense to ban that person from the next War. That way the punishment fits the crime.
Easy way to do this would be to keep a separate (private) list of people who are banned from War and Trials and just ignore Parasites when people are joining Trials or War.