Right - but do you see the difference in attacking a home system (a very normal and wildly accepted strategy) and seeking to deny (or occupy, if you will) a home system in perpetuity?
Well, there are differences. But then I do not think that any faction of any kind has any right to rule a system, regardless of whether it is the home system or not.
For every homesystem there are at least 2 and usually 4-6 factions that do not rule it.
Your question seems easy, but it isnt.
- It gets different answers in Barcelona and Madrid, Brussels and London, London and Belfast, Berlin and Munich, Moscow and Grosny, Moscow and Kiev, or Moscow and Kaliningrad.
- If Peter Peterson is in group X and thinks: Hey, if i do a PMF right next to group Z that we do not like, and Hans Hansen does the same with by creating group Y, and Berta Bertasdottir, Agnes Agnesdottir and Fred Blunt do the same with groups A, B and C, we will then claim "Hey Z, you cant expand into our systems, we are PMFs and this is our home system..." ... Well, i guess then group Z will probably not honor any "special PMF rights" and stay where they are, and rightly so.
- Same is true for enemy super power factions in other super power faction territory. Or by factions opposed to a powerplay ethos. Or by groups claiming systems from other groups that they have spend hundreds of hours to conquer, defend, build, write lore about, do podcasts, do community goals, etc.
So there really is no easy answers to this complicated question, apart from: you either solve any differences over the control of virtual territory by talking to each other, or playing the game against each other. And the last case will lead to the normative power of the factual.
Who controls the system controls the system.