There is much more on this in the section about the protein ratio for keto. For the purposes of this keto macro calculator, the important thing to note is that it has already taken into account that we're looking for a number that falls squarely in between the absolutely minimum amount of protein and an amount that supports muscle maintenance without going to the much higher end of the current recommendations from various experts.
Whether or not eating more protein on keto is "bad" is a matter that is highly debated in the community. Eating a higher protein ratio can theoretically kick you out of ketosis since your body can make glucose from excess protein. However, this isn't much of a consideration for most people. In general, the amount of protein the free keto calculator recommends will not kick you out of ketosi if that is a concern.
If staying in ketosis all the time is a goal, the only way to really know whether a certain type or amount of protein raises your blood sugar or kicks you out of ketosis is to test with a blood meter. The gold standard is a continuous glucose monitor, but you can also test with a blood glucose and ketone meter. If that is something that interests you, we have plenty of discount codes on meters.