"Speak only when it improves upon the silence."

- Mahatma Gandhi

You're asking the wrong question. You're asking "am I a pussy when my friends tell me to mix it up over Palestine and I don't want to?" This is a simple answer.

No.

The question you want to ask is "How can I get my friends to leave me alone on 'issue X' without offending them?"

Different question.

Your best move is to come up with a concise answer for yourself as to why you don't want to get involved. If you can write it on a matchbook it's short enough. I might start with "these are my friends on Facebook and I don't want to publicly pick sides in a dispute that is unfortunate, complex, and utterly without winners." You might go with "nothing anyone says is going to accomplish anything other than making everyone angrier, and there's more than enough anger already." You might say "I think the last thing my Feed needs is gasoline for the fire."

Did you know that you can "ignore" someone on Facebook without unfriending them? That is how my sister-in-law and I can avoid fisticuffs.

Don't tell her I said so.