"I know Jews strongly dislike Messianic Judaism but I have some friends who are Messianic Jews and I'm not going to say anything agaisnt them and it is kinda cool."
It may be cool to you, but to Jews, it is totally un-cool. It is a simple matter of identity theft. 'Somebodies' who is not Jewish or part of the Jewish Community anywhere in the world is going around calling themselves 'Jews'. In fact, they take it one step further and call themselves 'the only real Jews'. It is more than just an insult; it is an attempt to destroy Judaism. It will not succeed anymore than Hitler could have succeeded, but just the attempt is evil.
"I'm Roman Catholic and find it very similar."
Of course you would find Messianic Judaism and Catholics similar, you agree on the fundamental Christian common denominator: Jesus Christ.
"Anyway I went to a Passover meal with them..."
It could not have been a Passover meal anymore than a Buddhist monk celebrating the Mass. Just because your friends called it a Passover meal did not make it one.
"they used the Biblical quote "Do this in rememberance of me." to refer to the Passover."
I don't know why Jesus Christ did anything. Personally, I think that Jesus Christ is like Paul Bunyan and the Giant from Jack and the Beanstalk: a folk myth. Judaism, in general, does not think he did any of the miracles as described in the New Testament, from turning water into wine to being resurrected and ascending into Heaven. So, I don't think that Jesus Christ ever said "Do this in remerberance of me." Many Christian sources claim that Jesus Christ and his disciples were at a Passover meal and he pointed to one of the 4 cups of wine that are drunk during the meal and the matzah that is required to be eaten at the meal when creating the first Eucharist. Some disagree. Personally, since the prime component of the meal is not the wine or the matzah, but the roasted lamb, the Passover Korban [sacrifice], which is not referred to in the New Testament account, I question the historic validity of the entire story.
"I wanted to ask them to explain it but am afraid it might offend them."
I will make a guess. I guess that your Messianic Judaism friends will not be offended. It will give them an opportunity to 'sell' their religion to you, one more time.
Anyhow, I have tired to answer your question as directly as I can. If I can be of further use, just contact me.