I just hate the idea that I have to install an entire package manager simply to use some Node.js code, when NPM almost certainly could have done the job.
There's also a Docker option if you don't want to do that.
There’s a reason there’s 3 popular package managers for Node that aren’t NPM. Yes, part of that is the culture/ecosystem, but not entirely.
Being bad thereby creating desirable competition has lasting effects. We could get into when/why/what each thing supports all day, but it's not worth it.
Speaking of what's supported nowadays, installing other package managers is a corepack call away -- literally a whole other feature built into Node.js because NPM is/was/etc subpar. It's experimental, but this is all to say: it doesn't surprise me in the slightest that a project might use something that isn't NPM, and I actively expect it when picking up other's projects.