Not at all. Do you? Those are two very different things. In fact in the very next sentence he says "I'm not sure there is anything we can/should do about it now." Yeah, he's saying there may be nothing we should do now.
I would say OPM saying that he thought it never should have gone up in the first place qualifies as thinking it would be reasonable or appropriate to change it, no? Perhaps it wasn't accurate to say that I remembered "many" people thinking that, but at least a couple did, including me. And when someone said they thought maybe the feds would withhold funding to state and local parks/rec who had these sorts of things on display I said great, sounds good to me.
And nobody was laughing at it as impossible. That is a quick rewrite of history. One person maybe laughed at the idea of blowing a mountain up, but nobody's proposing that as far as I can tell
And the NAACP isn't asking for it to be "changed", they're asking for it to be removed. Quote - "The Atlanta branch of the NAACP is calling for the immediate removal of all Confederate symbols from Stone Mountain Park". They've suggested sand blasting it off.
And again, I don't see anyone who posted that they felt it "reasonable or appropriate" to remove or change the carvings in any way.