Most probably, the justification for 6k SM players from 4 chapters only would be: "Well, someone called by the Succesor chapters, and as their heraldry is almost like their progenitors, we can't distinguish one from another"

Everyone happy

also space wolves are not limited by the 1000 marine limit... i think there are more than 7000 space wolves

agreed

Then it is apparent you have not heard of Matt Ward.

Wouldn't adding an option of custom chapters solve this issue.
And it wouldn't even be lore breaking cause there're like countless later founding chapters throughout the galaxy that never got nor will be mentioned in official lore.

I don't know if they intend to make very specific gameplay for each of the 4 announced chapters but I honestly doubt. So that would leave us with just armor cosmetics.

But then how do you account for the ''hilarious'' people who make themselves rainbow coloured with a penis as their chapter heraldry?

Report + perma banhammer for genital heraldry
transfer to Chaos for pink/rainbow color scheme

These are simply extra zealous marines that want to distinguish themselves by expressing their preference for bright colors and sexual symbols. I don't see anything wrong with that. Every game with customization will have people straying of the normal color path. The developers should be able to control this fairly well by not making any penis-resembling symbols available, if they choose not to allow this.

But you cant not let people have pink on any other faction, even at that there will be people with genuinely awesome looking paint scheme by themselves not part of any clan (strikeforce) and it wont be lore friendly if they're by themselves. I know where your coming from and i wish there's a way to do it being lore friendly but i can't see it atm.

It doesn't matter if it resembles a penis people on games where you can design your own symbol always find a way, its admirable.... kinda....