It's nice that we have tunnels through mountains and bedrock.
If you have heart issues, you're likely taking nitro daily for chest pain.
So saying it's bad is 40% wrong at least. Makes ya think.
The best you can say is that dynamite was a safer alternative to preceding technology, and that its danger only comes under certain circumstances. None of that takes away from the fact that dynamite is quite dangerous when those circumstances arise, which is why it's commonly (and correctly) viewed as such.
But also, going back to the original contention - whether dynamite was neutral or positive for humanity - the destruction it and its descendants wrought in war is maybe more than counterbalanced by advancements in infrastructure. That said, if the industrialization and globalization it enabled leads to biosphere-destroying climate change, I would lean towards neutral.