I have been on both sides of the fence. So I can understand some aspects from both.
If you are selling 'something' at least $4-5+ worth, then you should be willing to answer questions on the item, even assuming that the 'write-up' online is comprehensive. Every contact 'could' be a potential buyer. I never take it personally. I'll give them a even handed reply.
As a buyer, sometimes I will spot a nice vehicle that is maybe 2 hrs away, but which may be slightly overpriced. I am willing to drive the distance and invest a considerable amount of 'my time' but I might want to know if there is room for negotiation. I generally would ask in that case that 'hey, I'm 2 hrs away, and would be willing to come over, and would your asking price be somewhat flexible?'. A lot depends on the answer. I won't follow up if the reply is rude or snarky. With a used car, just a important as the condition of the car is the attitude of the owner. That tells a lot of how well they may have cared for the car.
Just my 2c worth.