Started at a restaurant. Instead of butter or some other oil they use some butter alternative called whisk. Soybean oil based.
“How bad” is something that we can’t quantity directly yet. What we do know is that saturated fats are more good, and unsaturated fats (which have to be processed to make them shelf stable) are less good. I’m going to explain while leaving out the chemistry.
Every fat product has a combination of saturated, mono-unsaturated, and poly-unsaturated fats. Unsaturated fats “oxidize” more easily (hence the need for processing), and poly-unsaturated has more “unsaturated” parts so it is less healthy than mono. So saturated is better than mono-un which is better than poly-un, and anytime you use a fat/oil you’ll find a bit of all three.
Now take a look at a comparison chart like this one here:
Clearly coconut, palm, and animal fats are preferable. So what about soybean? Well soybean and olive oil have almost the same amount of saturated fat, but soybean oil is primarily poly-unsaturated while olive oil is primarily mono-unsaturated. This makes olive oil preferable over soybean if those are the two options. You can make these 1-1 comparisons with all the oils to roughly sort them from healthier to less healthy.
TL;DR Soybean oil is cheap and less healthy than most oils. A bit of it won’t kill you, but frequent consumption of significant amount can actually affect your health.