As long as you're not SPAMMING the groups.

If someone is sending you spam, you can block and/or report them.

That would be spam, wouldn't it?

I will spend thousands of dollars on travel and dining and las vegas gambling, but still wearing the same clothes I have been wearing for ten years because I am too cheap to pay for clothes.

And if the request you get has any type of spam in it, you would probably decline as well.

If so, that's because you've sent the same message multiple times, you've sent multiple message quickly or the recipients of your messages have flagged them as spam.  

You mention the "Contractor Wildcard" as a gamble.  

Cash flow properties are safer but I don't think investing in equity growth is "gambling" as many people state in REI forums. 

replying to spam accounts is annoying.

My wife and I have a small buy and hold portfolio in Memphis, and we would much rather hold on to a good tenant than raise rent and gamble on a tenant leaving, i.e. avoid the tenant search, lost rent and turnover costs associated with a changeover in tenants.