The problem is not Botting in solo/pg
The problem is you, as a PVPer, are chasing wild gooses in Open, faffing around doing nothing (actually complaining about soloers), instead of filling buckets like the people that are focused on their goals - and again, there is no goal in this game that is asking you to kill another player.
Edit:
Look at it like this
Let's say you're are part of an Open Only PP squadron. You have a certain percentage of "workers" - the ones that are filling the PP buckets - but this one is never 100% and they're running builds not that optimal for ferrying merits because they have to survive in open. And then you have the rest of the players as scouts, hunters and escorts.
While a smart squadron of equal size, playing in PG only - will have 100% haulers, all running perfectly optimized builds all focused on their goals and all being very efficient while doing so...
Guess who is the winning squadron and who is the looser (L) complaining about botting in solo/pg
The problem is botting only if botting is happening or felt likely to be happening. That is certainly true. Also your example demonstrates how dull and lifeless powerplay becomes when people maxmin in PG. Seriously, you might as well get a bot to do it, it's so lame.
Let me give you another example, your whole player group of experienced players never sees an enemy - so everyone can focus on PvE, at which they are very good. The contest is very important and your squadron are very committed, having laid the ground for the op for months. A group 1/10th the size claims victory against you in an otherwise equal contest. This involves the members of that group earning an order of magnitude more than you thought possible. Now perhaps they went without sleep for a week and quit their jobs. Maybe they have some new allies that you don't know about. But you have no idea, because you never see them. Meanwhile you know AFKing across an army of alts per player is something that can be done and has been done before. It's really got nothing to do with PvP combat. This is an exaggerated example to get it way over the line of where suspicions would creep in. The truth is, the limits of earning powerplay merits per hour have been well mapped over many years, so x10 isn't needed to raise eyebrows.
The issue is, and I'll reiterate, in a competitive feature, you need to be able to have confidence that progress is earnt through normal player behaviour. There is a burden on players, like it or not, to behave in a way that engenders trust across opposing sides, because actions can be carried out entirely in secret.