It's not that processed foods are particularly safe, but that meat is unsafe in a way we're accustomed to. Again: every year, meat-borne pathogens kill 5,000 Americans and cause illnesses in 1% of the population. Fake meats simply don't cause those rates of illness or death. If they did, the FDA would not allow them to be sold.
Who is to say that eating an equivalent amount of this fake meat product wouldn't cause a far greater number of deaths and reduction in quality adjusted years? It will be much harder to tell, because the problems aren't as obvious/acute, and there are always a huge number of confounding variables when it comes to nutrition.
Unless the problems it causes are acute, the FDA isn't going to have a very good way of comparing the safety of these with normal meat.
Among other things, sodium nitrate (included in the above description of fake meat) is, by itself, known to be more carcinogenic than red meat itself. But you don't see the FDA ensuring new foods don't use it.