If the way x is managing their network or (not) managing their customers means my network and my customers are affected ..
route leaks? packet kiddies? phish sites? spammers? whatever. If what you’re doing or not doing affects someone else, expect complaints, possibly to your upstreams if you aren’t receptive to these.
Not everybody mailing your abuse address is reporting random alerts their $50 home router’s firewall throws up, or is trying to spam you.
OK. All that stuff happens but is easy enough to filter out, and well, spammers who add an abuse address to their lists deserve all the blocking they get.
If you’re complaining about having to maintain an abuse desk or putting a dummy address into your whois records, sturgeons law says most of the time you’re the sort of provider who doesn’t want to staff an abuse desk.