What is he going to answer? Any reply at all from him/her would immediately be taken as an admission that posting about it online is the reason for doing it in the first place.
When reading stupid comments online, it usually better just to walk away. I try to do it most of the time, but even I get lured into it at times.
This assumes the parent comment is silly. But it brings an interesting point -- besides "I really like it" (which of course happens) there is also a whole "macho"/outdo-the-other culture behind eating spicy foods. People regularly brag about it -- in no ascertain terms, heck, there are even sports-like competitions and shows.