Its not conflating two different things though is it. Your claim is that Iran is arming proxies and attacking US soldiers. The opposite side is that the US is arming proxies that are attacking Iranian soldiers.
On a very simple level... it seems to be what people like to do these days. The US has funded rebel groups in Syria, that isn't with the intent of specifically going after Iran but rather they want to back group's opposing the regime (and for good reason!) - yes Iran is supportive of the regime.
That is somewhat different to actually backing groups and guiding them with the express purpose of attacking coalition forces - that is something Iran has done on and off for several years and well before the Arab spring/Syria etc..
That extends way beyond just supplying arms too - when the local Shia militia groups used to carry out attacks at Basra airport because the nimrod had been spotted on the tarmac by one of their dickers working on base then they were doing it on behalf of... you guessed it: Iran. Back when they couldn't penetrate the armour on British warriors (APC vehicles) guess which country stepped up to supply a different device... in fact guess which country funded most of them and was basically behind policy and whether they were going to carry on killing coalition troops or stop for a bit and only kill the new (at the time) ING (later absorbed into the Iraqi army) or police etc.. that got rather confusing as some police units were infested with Shia militiamen anyway so you'd get police cars attacked and the people behind it were in the same militia as some of their police colleagues. It wasn't just funding either - they directed this stuff, they had republican guard types in country.
And as said, yes I agree, the US acted in response to aggression from Iran. Yet you consistently fail to admit that Iran acted in response to aggression from the US.
Because they didn't - you're insisting on conflating different things - taking pot shots at the coalition in Iraq pre-dates anything in Syria... I'm well aware that the US and Iran have history but you might as well come up with some argument about the US was the aggressor because of X event in the 70s or 80s etc.. when it is BS. This was an attack in response to Iranian aggression, in Iraq, something that hasn't previously been responded to with direct action in this manner and has been going on for a couple of decades!
If you refuse to grasp even that simple fact then there’s no hope in continuing this conversation.
If you carry on making simplistic comparisons, expecting acknowledgement of "simple facts" to build simple arguments with no room for nuance then yes, you're right, there isn't much conversation to be had.