The 'internationally-recognized government of Syria' has run an internationally recognized ethnic cleansing campaign against the country's Sunni population, the vast majority of it hasn't been a part of ISIS (Maybe you have a problem with the map, but the Yazidi genocide happened in Iraq). Speaking of ISIS, maybe if Assad didn't intentionally release jihadis from Sednaya, or didn't support their previous incarnation in Iraq, we wouldn't have these problems. That's why there are complete sanctions on Assad, which will not be removed until he falls.
As for the gas massacres, the conspiracy theories just get madder and madder. Obviously, the rebels are supposed to have attacked themselves for the XX time after seeing all the previous gas attacks led to no reaction? While never ever using them against Assad troops? The Assad regime being the only one in theater with the equipment and capability of staging a gas attack? Some people are just shilling for mass-murder.
The Iranian government isn't elected. Everything is controlled by the Supreme Leader and IRGC, and the 'elected' offices have no power. The 'elected' offices where the only people who are allowed to be elected are those that support the regime[0], and protesters are killed[1].
You're right about one thing - the Saudis are not much better. Then again, they didn't support a WMD attack and deny it later, like Iran apologists do. Nor do they officially have genocide aims against other countries. Maybe the apologists secret admire the Mullah's aims, and that's why they defend the regime.
[0]
https://apnews.com/44ad5910fa3e1a297d6c0b5ad6c3c59f
[1]
https://www.reuters.com/article/us-iran-protests-specialrepo...