Er, you've been a bit selective by putting up just that chart. That chart is for damage per energy, and only considers damage vs shields (which to be fair is the only thing the excellent people who did those tests could properly measure) - i.e. how energy efficient the weapon is, not really how damaging. It doesn't really tell you anything about how much damage it'll put out, just how quickly it drains your WEP capacitor when you fire it.
The Plasma Accelerator is for single-shot alpha-strike damage. Even DPS isn't a very good way of measuring its capability. That's before you even go into how good it is at melting subsystems to slag.
But let's take DPS:
View attachment 70888
And then damage per shot:
View attachment 70889
Doesn't really look that awful, hm. In fact, it looks the opposite.
In actuality of course, you have to be able to aim a PA, because they only come on fixed mounts, so it's more complicated than a simple graph.
But uh, since I assume you'd seen the rest of that thread that analysed weapon capability vs shields, and that's where you got your picture from, you already knew all this?
Are you just trolling? Or is this an Eve-style meta-gaming in the forum thing, trying to drum up outrage so the devs buff a weapon for your benefit and at the expense of the game?
For those who are interested, the original thread:
https://forums.frontier.co.uk/showthread.php?t=140240