Why would you care where/how someone acquired their gear? They put in the effort to earn their rewards, enjoying the game the way they wish for the same monthly fee as you, and if they want to enjoy multiple facets of the game, I don't see why you would have a problem with that.
If they are doing their share of the work in the group, it doesn't matter what gear they have on, because they are contributing ... if they aren't ... still isn't a gear issue, and either you should discuss the removal of them from the group with the rest of the players in it, or leave the group and form a new one with players who feel all need to contribute equally. If you just want people to have specific gear, then by all means, form your own group to accomplish the group makeup and gearing that makes you happy.
This is the freedom of your choice to play with who you wish, and form group with like minded individuals, the same as it is your choice to not play with people with do not share your ideas/ideals ... but it is not your position to tell everyone else that plays the game that they must conform to your specific desires on the correct and wrong ways to play ... for that is personal opinion, and you can solve the issue you have by simply forming a guild and only doing the FP/HM/Op with people who agree with you.
You earn the gear and the mods in it. It is your gear. You have every right to use that gear and the mods in it, however you wish for that character. Freedom to use the things you earn and worked for.