Freegate is a proxy tool helps users in the censored country surf the censored webs, it is a Windows suported software, but Wine suported too. Few months ago I tested it in the Whonix Workstation it can run and I could surf the web through it, but now it could not connect again.

I use it to avoid website knowing myself a Tor user because some websites block Tor user from, for example, having comments, how can I make Freegate connected under Whonix?

This is an indication, that you know how to use it. Since it stopped working without configuration change, it’s either a bug in Freegate or perhaps Freegate stopped accepting connectors coming form the Tor network? Sure, there is still the possibility, that Whonix is the cause of this issue, but rather unlikely. Perhaps ask the Freegate maintainers?

There are lots of such censorship circumvention tools. We don’t have instructions on how to use them yet. There is a development ticket ( waiting for someone to take it. That someone could be you.