I think the issue is that the germs get mixed to the center instead of just the outside? So with steak the outside gets throughly cooked? But I’m not sure. But I imagine grinding it yourself or from a good source would be perfectly safe and I’m sure grinding steak would be too. My brother, on the other hand, does not buy the good or special burger and just buys regular ground burger and he will also get it that way at restaurants too. Technically they’re not really supposed to or allowed to serve it that way here but most of them do anyway or at least as rare as they are allowed haha