The available slots are member slots, but I see a number of apps coming from higher ranked users. I do not think this is wrong, but why do we not provide opportunities for those with according to the needs of the current campaign to get it ?

There are more campaigns that can receive higher rankings, and fewer campaigns that require lower ranking participants. You should consider giving opportunities to those lower ranked to fill the slot. I think managers should consider it because this forum still has users with good quality posts despite their low ranking. Just my opinion.