To be honest, I suppose you could! Still, there are SOME specifics set out in the Bible and, for myself, I think the Mennonite's core beliefs line up the closest with what God lined out for Christians in the New Testament. For that reason, I really don't want to be part of any other church. I don't believe, however, that all the Mennonite's applications are nearly as "Thus saith the Lord" as we like to make them sound. For example, I don't believe a cape dress is the only way to be modestly dressed. I've seen plenty of cape dresses that are anything but modest depending how they're made! But, for myself, I think it's a good application. It's what we both grew up with; it's what seems respectful to both sides of our families so it's what seems right for us at this point. But that doesn't mean it's the only way.
I guess that's what I've been trying to say. Most Mennonites can't be honest enough to say "A lot of what we do is really tradition, not right or wrong." If they say that, their whole belief system is suddenly threatened! So, instead of opening that door, they try to keep everything inside of 'the way we've always done it.'
There is freedom in being able to open that door and say "I know I don't have to be a Mennonite to get to Heaven. I know dressing this way, doing these things, aren't the only way to live out what the Bible says, but I don't think it's a wrong way, and for me -right now- I think it's a good way." And I know. Saying it and really living that way are two very different things. How well I know! But I think it's the right way.