So you play only objective modes in Mosh maps with constant action? No wonder your SPM is high.
Way better than FFA and TDM where everything is slow-paced. How do you expect to have a high SPM just playing those game modes? Plus getting Scorestreaks are so fun. Five kills for a UAV in TDM? Hell no.
SPM only matters combined with a good KD, since it means you aren't just rushing in getting 1 kill and 1 death and getting high SPM.
Alone, KD is more indicative of skill at this game.
Getting one kill near an objective and then dying isn't going to get you a high SPM, for that you need to be calling in scorestreaks, capping/defending objectives, and disabling enemy kill streaks and equipment.