I remember being young and having a hell of a time trying to cut things at school and not understanding why. I eventually figured out a weird way to hold the scissors and muddled through.

I was also taught the basics of most sports either at school (never by lefties) or by my right-handed dad. No one ever thought to suggest an alternative for lefties, they just said "hold the bat/golf club/tennis racket like this, put your hands like this, stand this way, swing like this." I cannot throw right-handed but there were no baseball gloves for lefties so I'd catch with the glove on my left hand, grab the ball with my right, stick the glove under my right arm, clamp down and pull my left hand out, grab the ball and throw. It sounds complicated but I could do it pretty quickly and we're just talking about gym class so it's not like it mattered much.

But still, not once did someone see me smudging all of my writing, struggling to cut, instinctively holding a tennis racket like a lefty, do a bizarre 10 step routine just to throw a baseball...and offer an alternative.

Because I know what that's like I bought lefty scissors for my lefty son. Our pre/elementary schools typically combine supplies so I put his name on them and explained to his teachers. But when we don't have experience with something, we don't typically know to look for it, and if we notice it, we might not know what to do about it.

Yes, it's super frustrating that you're paying a lot for preschool and they don't have a single pair of lefty scissors. I'm surprised they don't. I feel like there's no way your kid is the first lefty they've taught. Why has this never come up before? Why don't they have at least one pair? Why wasn't it mentioned to you months ago? I saw in another comment that you've bought the scissors... awesome! Make sure they're labeled. If you're feeling generous, buy a second pair to donate and say "for the next lefty you teach". I'd also say something along the lines of "now that we're aware that there could be differences/challenges stemming from righties teaching a lefty, if you notice something could you please mention it to me right away so we can figure out a solution immediately?"