Maybe they should swear in on a guillotine.

So basically anyone who wants to come here can come as long as they are law abiding and not diseased or whatever?

How do you have open borders and yet restrict criminals or suspected terrorists from entering? Either you have no restrictions or you have some restrictions. If you have some restrictions then you will have illegals that need to be deported which means you will need some kind of enforcement to do the deporting. There is no feasible way to run a modern country with truly open borders.