alt Hacker NewsRange being worse with a fully loaded car than with a lightly loaded car isn't exactly news, and not exactly limited to electric cars. I can clearly feel my old diesel struggling more when I'm driving 3 friends and with loads of heavy stuff in the back than when I'm alone. That makes the gas bill more expensive.
You probably know already, but ICE cars only convert about 20–30% of fuel energy into motion, while EVs are often +90% efficient. So when an EV has to work harder (extra battery weight or colder weather), you notice the drop in range more.
In an ICE, the same load is less visible because most energy gets wasted as heat. This is also why cold weather seems to affect EV range more.