Water swirls because it's the course of 'least action' for the draining process. It creates a laminar and continuous volume exchange through a hole. Pipes are usually filled with air which has to be exchanged with water to drain. Physics just optimizes itself to be as efficent as possible with this. You can't have a perfect draining surface so so currents in one direction will always be a little bit stronger that in the others. Gravity applies a constant acceleration, so this small difference in initial direction will be amplified over time creating a swirl.
In case of a toilet though, the water is already introduced in a swirl during flushing. So none of the above even matters.
The coriolis effect has nothing to do with this. The coriolis 'force' is not a real force, it's just the product of things trying to move in a straight line on a rotating surface which to observers on that surface looks like a curve which implies a accelerating force. Usually this applies to things flying through the air, because the are moving independent from the ground. Something that is not a force can not influence something like the water in a thub.
What people confuse the coriolis force with is the centrifugal force of the earth's rotation. But this force increases radialy but is tangetialy evenly distributed, which means it's symmetrical so it doesn't matter which hemisphere you're in. It doesn't point 'left' or 'right' it only points 'out' or 'up'.
Unless you're right on one of earths rotational axis none of those effects matter.
Oh, friends assume sexual preference based on other things too. Like the way you eat a hotdog, what kind of car you drive, how quickly you can recognize that the song is by Kyle Minogue, how long you hold a sloppy french kiss with your homies, wether you you sit with your legs crossed or slow down on a yellow light.
How can rats have human level intelligence, if we as humans have to essentially consume the whole bodyweight of a rat daily, just to sustain our very energy demanding brains.
What does that mean "refrigeration tech [...] energy hungry"? The technical appilcation of the Carnot-Cycle is as close to maximum mathematical efficiency as we can get. Sure, it's far from 100% efficient but we're actively going against entropy here. In the end it all comes down to thermal isolation and losses. Even cheap fridges from the past 20 years take like 100 Watts once they've reached their target temperature. That's only a bit more than a laptop and a bit less than a desktop computer on idle. AC-Units take a lot more but we already have a 100% efficency solution, it called "not bitching about the heat".
I make my bed every day.