Good day,
What was written on there isn’t correct in the first place as it completley misses what a relay truly is. Simply assuming that any kind of taken over relay can tell you the IP address of the people using said relay at a certain point in time cannot be correct for several reasons, mainly though, because there are different types of relays used for every connection which goes through Tor.
Regard this for more specific information of the different types: https://www.eff.org/torchallenge/what-is-tor.html
To answer the question, only one type of the three different relay types, the entry node is aware of the IP-Address you use to access Tor. This however is not a vulnerability in any way and actually necessary for Tor to work at all. This isn’t an issue because any traffic going through this initial relay is encrypted. The person providing this entry node (no matter whether it is a private person, an organization, or law enforcement) can thus only know that someone with a certain IP is trying to access Tor, but not what he/she is doing.
Also, Whonix does not modify Tor in any way shape or form.
Have a nice day,
Ego