The Gorn didn't want some land, they were repelling what they considered invaders from their land.
I've never understood this idea that since the Federation likes to explore they should be able to roll into others space without repercussions.
The problem isn't that the Federation likes to explore or the Gorn want the Federation off their land. The problem is that no one
in Trek seems to think putting out some sort of probes declaring XYZ is part of their territory is a good idea or if they're not going to do that, have some ships stop by before
the Federation makes colonies there and is justifiably pissed that their people were murdered by aliens who put no claim on a planet.