They are not the same.
For example, KPN in the Netherlands is not free, and xfinity wifi in the USA is not free.
For this to have any sort of credibility, there needs to be a discriminant filter mapping truly free vs open hotspots.
For me this current map is too noisy to be of value. Try using it for free internet, and you too may run into disillusionment and frustration.
Oftentimes, the operator will send you an SMS with a one-time password, but they require a local phone number to send it to. Or they use your phone number to de-anonymize you, so it must be a phone number from their local country.
When traveling, this makes these "open" access points effectively useless, unless you decide to spoof another person's MAC address.
For instance, how would you categorize a wifi in an airport which needs you to fill a random form/survey (not paying anything) to access the Internet? Same question if it is then limited to something like 10 minutes (and you then need to pay, or just trick on your macaddr/dhcpname/...)? In these case, you can actually access the Internet for free, but they are extremely annoying.
Note: these kind of wireless network are actually very common in some places
(Disclaimer: I work for the company who implemented that network.)
Some crucial filters:
1. Free vs Non-Free
2. Free time limit
Some nice-to-haves:
1. Average bandwidth
2. Cost per unit time
They come and go.
Also mark 'expired' and 'verified' hotspots as such. Most will be unverified, of course.