The owner of the site does make money from the advertisements. Whether it even covers the cost of hosting the site, I have no idea.
You are correct that the rest of us are volunteers. You do have every right to post your question anywhere you want, but you show a complete disregard for the people you hope/expect to help you when you cross-post without advising them of it. Just as it's your right to post wherever you want, it's their right to ignore you once they realize you have no respect for the time they're willing to donate to help you.