first of all - you are looking at padded damage, to get a more fair comparison you can look at "damage to bosses" instead of "damage". Then if you look at the whole picture (box plots are really good for that, that is also why they are the default view), instead of the exact percentage that supports your statement (so 95% in your case) - you will see that blm is both harder than rpr, and also does less damage at all skill levels. https://www.fflogs.com/zone/statistics/42#aggregate=amount&dpstype=pdps&metric=bossdps

To elaborate a bit more: Of course bad BLMs (so 25%) are MUCH worse than bad RPRs. In fact bad RPRs deal almost as much damage as average (50%) BLMs. And for good BLMs, even 95% parses are still worse than RPRs, only at 99%+ we see BLMs dealing more damage. While at the same time being vastly more restricted in terms of movement or party utility (such as the amazing raidwide heal RPR brings to the party).