First I heard of this, but some quick Google searching shows there is something to it. Taking precautions helps, but most of us probably don't.
Is it okay to feed hummingbirds?
https://spca.bc.ca/faqs/hummingbird-feeders/
No hummingbirds here yet, but they should be arriving any day now, they come for the spring wildflower bloom in the mountains. This should be a really good year for that.
Not mentioned in this article, but in another, which I can't find now, this fits with my personal observations that hummingbirds are aggressive over their food supply. I watch them chase other birds away, and I can't see what happens after they chase out of view, but I have seen videos deadly hummingbird attacks on other humming birds.
Also, hit upon indirectly by your article is that feeding tends to keep hummingbirds from migrating, which can trap them in winter conditions that they are not evolved to cope with.
But none of this surprises me as feeding wild animals is not recommended, even though it's fun to do. And I've done it too. In Montana, the Department of Fish and Game asks people not to feed deer, but there are no laws to prevent this. My friend, a game biologist with Fish and Game, says the agency has just thrown up its hands and backed away, because people won't listen. The outcome of deer feeding can have devastating impacts on local deer populations. They congregate around areas of artificial feeding, where they get only enough to keep them in the area, and then they browse everything else to death. As the deep snow comes, which unlike cold temperatures, forces them to expend large amounts energy wading through deep snow to find more food when they are already in near starvation, and they die.
I think it's best to leave nature alone. It has managed to do well without human intervention. It can be enjoyed just as well by leaving it to do its thing on its own. I think it might be a better idea to plant flowers in your yard to feed hummingbirds, but I'm not an expert. I have just had information that has convinced me to leave wild things alone.