There is, you just didn't realize what it was telling you. Planetary Defense kills a % of your troops before they even manage to get into the atmosphere. You can see this as "Neutralized By Defense". Once you land, it's Resistance that determines how hard the defenders actually fight.
This planet has 100% Planetary Defense, so it is killing every single soldier before they even get close enough to open fire.
Alright, but I maintain that the interface is misleading. It seems to suggest that the 100% "Neutralized by Defense" is countered by the 55% soldiering bonus because (1) they're listed in the same column and (2) 55% - 100% = -45% and 24 - 45% = 13.2, the listed "Invader Power." In addition, the interface claims that I will suffer "Low" casualties and the defenders will suffer "Very High" casualties, which is not true.
Planetary Bombardment isn't working because it reduces resistance, not defense. You'd need to use Biological Warfare to reduce Defense. I kind of understand what another poster was saying about how Bombardment should reduce Defense, and Bio Warfare should reduce Resistance, but that's not how it works right now.
Now I know. By the way, was this indicated somewhere in game but I missed it? I wish all strategy games would rip off the idea of the Civilopedia, it's very convenient in cases like this.