If you have written a post and someone replies to it and is actively responding to your questions, deleting the post *in the middle of that conversation* is like putting the phone down. This is not Facebook where everyone does what they want on their own page, this is a members' forum where we communicate with each other. We're not robots, we're individuals who are taking time to participate here.
You don't have to take advice from anyone, you don't have to like what they say to you and you don't have to engage. Feel free to say 'Thanks for your thoughts but I'm going to go in a different direction' or 'Thanks for the convo but for my own reasons I feel I need to delete this post.' Whatever is on your mind, do tell. But if in the middle of a completely cordial discussion you delete the post without warning it is disrespectful and rude, even if that was not your intention.
This happens so rarely it seems like overkill to trouble you all with it but of course I can't say this directly to the relevant person as they have deleted their post.