What is the deal with bans for "proxy/vpn exit node"?

I get them almost weekly and always appeal them and they are always removed. I think they happen because I frequently use public wifi that has a captive portal (xfinitywifi).

I bought a pass a few years ago and renewed thinking that this would show that I don't post bannable content, but apparently this is something automated in the 4chan server system. Would it be wise to implement something that precludes pass users from receiving these autobans based on where they are logging in?