It's the idiotic MLB blackout rules. For some reason, they identify three "home markets" in the Memphis area, and it's the three you mention. So, if you are streaming on an app in Memphis, those are blacked out, because if you have local programming on xfinity or dish, you get those games as part of your local sports package.
If you're a fan of a different MLB team than those three, and you watch their games on Extra Innings or MLB TV, they get blacked out if they play one of the three local teams, forcing you to watch the local broadcast.
I understand blackout rules in the 1980s. But they're stupid today with all the options out there for streaming and viewing games. They need to come up with a better plan.
And as far as Memphis "home teams".....I get St. Louis. It's right up the river and their AAA team is here. I get Atlanta. It's six hours down the road. But Cincinnati? That doesn't make any damn sense.