Again, you're looking at secondary matters. Look at the consequences which results due to the primary intention.

Besides, nobody opens up their houses for strangers. So it is a flawed comparison as well. You need to be honest with the premise. You are talking about an online community which is built for a purpose. Your purpose is two-fold. You want to be a nice contributor towards some ideal (nothing wrong with that). Your second purpose is to be self-sustaining (so you can continue your goals). Again, nothing wrong with that either. But none of this has anything to do with open and inviting house, or even strangers. But look at what your purpose does: it necessarily invites strangers. You then have consequence.

You also know in your heart of heart, that if you do not invite strangers (let's also remember that we're talking about the online world), you will never be able to achieve your ideals. Because no matter how big your social circle may be, you cannot achieve your ideals through just the people you know.