That might be overkill but it's possible he had a bad experience having something of his ruined by a careless angler.
Look at both sides of the equation. I cannot begin to tell you how many people on my lake have had damage done to their property by careless anglers, including myself. I had a large hole ripped in my boat cover a few years back and always find lures hanging from under the dock or posts which could dislodge and get stepped on. My neighbor had some wiring ripped out from underneath his pontoon boat which was not cheap to fix. I love dock fishing. If I hang a lure up, I make every effort to retrieve it without doing any damage. If I hang up under a boat, I just cut the line.
If I land a lure on or in a boat, I will make every effort to retrieve it instead of just yanking it. 9 times out of 10, that will only make things worse. If the homeowner comes out while you are doing this, calmly explain you made an errant cast and want to retrieve the lure without doing any damage. I've had people hop in the boat and dislodge the lure and toss it out to me and say try to be more careful. If someone dings your car in a parking lot I would wager you would be pretty upset and have some choice words to say to the culprit. Flipside, how many of you actually leave a note on the car after you have inadvertanly caused damage.
If you walk out of a store and see a big scratch on your car, you're going to be p.o.'d and be more leary of it in the future.
Landowners are probably the vast minority on this forum, but that does not make them jerks if they are concerned about their property. Per above post, some do go to extremes and gt wacky.
Not to mention all the garbage and cans etc. that lazy anglers toss overboard they have to clean up. I'm sure these anglers are in the minority but still gets people p.o.'d.
2 sides to every story. Be courteous and you'll be surprised the reaction you'll get.