This could not be further from the truth.
Everyone, repeat after me; There is no manipulation made to the MM based on a players skill
Players who play in three man divisions (often with those from the same clan because hey, they're friends) have better chances of winning due to external factors such as:
Compounded individual skill
Use of external communications (voice coms)
Coupling of compatible ships that work well together
But again, and I repeat; There is no manipulation made to the MM based on a players skill
The only "sway" on MM has to do with how often you get up-tiered which was released with the last patch.