Google removed "Reply by chat" if recipient is off-line. Insanity

If I got a question via chat when I was off-line, I want to respond via chat as it's important (at least to me) to preserve discussion continuity. And that is also what "reply by chat" is for, to not start new conversation. Not everyone is on-line all the time, so it's fine to reply even if my interlocutor is not on gtalk/gmail/whatever right now.

But since today (or maybe earlier, but I did not notice it before) I cannot (seeing only "XYZ is not available to chat") and it's ridiculous. Don't you think?