I guess you're talking about the HMA browser extension.
The proxies you get there are public and available for everybody so you basically share the same IP address with other people. What this does is make the proxies slow, unreliable and, depending on what you need the proxies for, you risk getting your IP blacklisted from various online services, for example, YouTube.
I highly suggest you get quality private proxies instead of using public ones.
Oh, by the way, next time post in the right forum section.