Riddle: Safety in numberS

My last one charged politically
aimed at those who show hypocrisy
if you want the bounty worthy of a Spartan
then hearken here and answer this jargon.

I am the reasons why you burn
well after you're left in the end of your turn
a plethora of actions lead you here
under a septenary of hate and fear

Situated here, desolate of fortitude

just moulded eyes and tunnels of feud
for an act of me is negligible advice
my existence defended by who surmise

No patronising statement here
no tarnishing or reputational smear
just read the lines and think it through
revive the fun in riddles anew.

Answer

I think this is related to

The Seven Deadly Sins

Reasoning:

I am the reasons why you burn well after your left in the end of your turn

Taking "burn" literally, these actions will send you to Hell. The end of your turn meaning once you are dead.

a plethora of actions lead you here under a septenary of hate and fear

There are many reasons (a plethora of actions) one might commit any of these transgressions, but most of the time hate and/or fear are involved, as any good Jedi would tell you. In addition, septenary directly links to seven.

Situated here, desolate of fortitude just molded eyes and tunnels of fued

"Desolate of fortitude" means you are lacking resilience, and cannot stop yourself from committing them. Molded eyes and tunnels of feud sounds like some depictions of Hell from the Renaissance era to me.

for an act of me is negligible advice

I wouldn't advise someone to commit these acts.

my existance defended by who surmise

The existence of "sin" at all is defended by religion, which is literally people who surmise (suppose something to be true without confirming evidence).

In addition, the title has a capital S at beginning at end instead of the usual title case: Safety in numberS, so the answer could be shortened to

Seven Sins