It also sounds like they're promoting yet another way to make "the internet" slower, more bloated, and have greater impediments to usage.
They lost me more than a decade ago when they hoovered clear text passwords from their wifi scanning and blamed it on a single engineer.
I don't see how advertising an open WiFi network is much different from advertising an open house. In both cases you should expect visitors.
You can take advantage of it, but almost everyone is going to feel like it's not right unless they have consent.
An open house would be akin to have an open wifi network labeled "PleaseUseMe".
A better analogy is:
I leave my door open with a welcome sign out the front.
Two people enter.
One of them picks the pocket of the other.
And then the thief blames the guy who told him about the open door in the first place.
I don't find it particularly troublesome that maps of open WiFi networks exist.
I do not, however, think that it's okay to behave maliciously, or inappropriately on open WiFi networks.
My earlier response to your comment about hoovering plain text passwords didn't properly acknowledge the bad behavior that took place. I concede that you are correct, it was rude and insidious behavior.
It was never the connecting that bothered me, it was the storage of the data encountered.