Addendum: I manage a very small open-source product (https://www.planimeter.org/grid-sdk/), and when you're creating something that competes with an established incumbent, all you can do is your best and focus on the most impactful features. Individuals like the one above saying things like, "I'll be avoiding parcel like the plague," is really disheartening, but try and focus on their concerns more than the actual words they use.
Frustrated people are a goldmine for feedback that many projects simply do not receive. Take it in stride, know that you have something others do not, and use it to your advantage. It can be hard to separate your feelings from the words used, but there are diamonds there.
If you can find one, you can find ten. If you can find ten, you can find a hundred. And so on.
It’s also extremely important to remember that the opposite of love is not hate, negativity, or criticism. It’s indifference. Harsh critics can become some of your best users/customers/advocates if you’re able to learn from them and win them over.
It's tough to separate my ego from my work.
Sure the out of date dependancies thing could be seen as a problem with post-css plugins that require a newer version, but the unfortunate fact is that in webdev land, everything seems to evolve at a breakneck pace, foregoing backwards compatability. And when some part doesn't match, the buildtool suddenly becomes unusable. (webpack is way less easy to setup, the flipside is you can for example choose your postcss version)