Anything can cause damage if you do it like a wild animal. If you push on the strut near the attach ends it would be hard to hurt anything. If you push in the middle you can bend them, but sometimes when I'm lazy I'll push from the rear near the jury strut. I wouldn't do it if it were on soft or rough terrain, which would require a harder push. All those words I just typed are too many when it comes to writing the manual, and there's no way to tell how much common sense the reader has. It easier to say "dont push on the strut"
Hag