What happened to commenting on youtube?

I'm no longer able to reply to a comments on youtube. Why is that? Is it because I don't want my google name to be my youtube name? I've kept the name I use for each separate/different because I've had someone who deliberately looks for my comments on videos and replies to them by sending me spam. And in this day and age you must be careful. So I don't want youtubers to know my real name and start looking for me on the net to do who knows what. But is this why I can no longer reply to a comment on youtube?