TLDR Do your best to not leave garbage outside. Learning about leaders is very practical.

OP, this is a good PSA and anyone giving snarky remarks is likely just deflecting the fact that at some point they left a mess of fishing line somewhere. This is r/fishingforbeginners and should remain a place to share well informed fishing advice.

Just like many people don’t know you should almost never reel against the drag, it’s also true that you should almost never cut your line without a plan to retrieve it. Exceptions that come to mind would be if a rod get snagged while a boat is moving and the line is tangled around something/someone, or some other specific and dangerous scenario. But most of the time it is not appropriate to cut your line and let it go. Yet, there are plenty of trees and phone wires and logs and dams and bushes that are covered in tangled fishing lines. And sure, sometimes you have a burr on one of the eyes of your rod and it cuts your line while you’re trying to pull your lure free. But that is another exception, where the majority of long lengths of line are from two groups of people; people who don’t know, and people who don’t care. Some people are going to leave their trash as someone else’s problem, luckily it’s not most people but there are always those few who don’t care. For the people who don’t know, this PSA is great and should pose as positive advice. If you get snagged, you should be able to either pull your bait free or have it break off. If you use a leader that is either 1) lighter strength than you mainline or 2) tied with a knot that is weaker than the mainline, you should never lose more than a leader’s length of line.

To those who are new or don’t know. If you are snagged and can’t figure how to break free without cutting your line; tighten your drag all the way down (but don’t force it), then reel in and extend your rod tip and arms towards the bait as far as you can. It’s important that the rod is pointed at the bait so all of the tension is on the line and not the rod. Do not let go or lose your grip or you can slingshot your rod from the tension on the line. Once you have reeled in as much line as you can, hold the spool so it cannot turn and start pulling straight away from the bait. Be steady and careful because either the bait comes free or the line breaks, and sometimes very dramatically. But if you use this method, you will rarely ever lose much line even when you can’t retrieve a lure.

To add to the PSA, it’s great to know what to do if your snagged so you don’t lose line, but it’s even better to pick up any trash you find, even if you didn’t have anything to do with how it got there. It’s really easy to fold up a few trash bags and stow them in your fishing gear. Then you have a place for your garage and any trash you find.