Well yeah. Though Vent, Teamspeak and Mumble never had these issues (if you could trust the server admin).
Skype (at the time, no idea now) was a very shoddily written piece of software. It was trivial to query the IP of any online user, even if they were not on your contact list or appearing offline.
You had to use a VPN or carefully conceal your Skype ID, I did work with a somewhat popular live streamer back then (so a VPN wasn't feasible), and their ID was a very random string that was not to be shared under any circumstances.
Skype (at the time, no idea now) was a very shoddily written piece of software. It was trivial to query the IP of any online user, even if they were not on your contact list or appearing offline.
You had to use a VPN or carefully conceal your Skype ID, I did work with a somewhat popular live streamer back then (so a VPN wasn't feasible), and their ID was a very random string that was not to be shared under any circumstances.