Well if it's their property, they have every right to be unhappy.
People were constantly going across ours tearing stuff up and leaving trash. I put up fences and gates they would tear them down, so I put up HD security cams with night vision and got their faces, luckily they were known to the county sheriffs for other things, ended up taking them to court and they had to pay to fix the fences and all the damage they had done to land, a estimated cleanup cost, previous gates and fences. We let the neighbors with horses and ATV/SxSs cross our land but the non-local ATV riders were less respectful, tore up fences/gates, left a lot of trash and damaged our creek banks and treated the creek like a mud pit which really cut down on the quality of fishing, I want to be able to share that experience with my kids and I want them to be safe if they are playing on our land. Someone riding through at 62mph could easily miss them and kill them.
Really wouldn't have cared if they'd been more respectful and "tread lightly". I knew when we bought it our land had trails across it that lead to a LOT of better riding but it is OUR land if you're going to cross it be respectful and considerate that it is not yours.