A question regarding etiquette

I’ve recently come across a situation where I’m just not quite sure what the right thing to do is. Normally these things are instinctive, but here, well, I hesitate, for reasons that may soon become clear. To wit:

Let’s say you have an acquaintance on FB – someone you were peripherally friends with a long time ago (friend of a friend) – and you have them as a friend because it’s a way of keeping up with someone from your past, who you probably will try to get together with at some point. Even though they post odd things about their horoscopes, and what God said to them today, and so on. Note: I think god’s too busy to be talking to all of his children directly, m’kay? And even if he were chatting up a storm – it probably wouldn’t be via a Facebook app. I’m just sayin’.

So this morning she posts the following: “Susie Silly*” keeps seeing 11:17 & although I know some numerology I'm no expert... anyone have any insight or suggestions?

My question - would it be wrong if I went with my first instinct and responded simply but helpfully with “Umm, yes, it means that you’re batshit crazy?” Or would that somehow be considered a bit rude?

You see my dilemma.

As an aside, I’m realizing how useful Facebook is in some respects, particularly with regard to separating the wheat from the chaff, so to speak. In the olden days, it might take months if not years to discover that people you considered your friends were insane or unstable or flaky or ignorant or bigoted. People can be amazingly good at hiding things. But on Facebook, between the games and links and posts and groups and fanpages and extremely religious right-wing rantings, it’s pretty easy to figure out where people stand. And then hide them. Quickly.

*Name changed so I don’t look like a total meanie.