I think it's best to first separate the topic into two parts in order to answer your question fully.
(Plan A: "regime change") The US has been meddling in Syrian politics since the 1940's. In an article that I posted today on Steemit I discuss the plans that were made spanning a decade. I purposely only went over a decade of information due to the sheer volume of information. To go over all of the information I have gathered through my research from the 1940's till 2011 when the war began would be far too long for one article. I am actually working on a prequel to that article that I will most likely have out next month. In that upcoming article, I will go over plans from the 1940's till 2001. Which is where the article I posted today begins. Now I would call this part the US's Plan A. This is where they tried to carry out "regime change" by ousting President Assad, and putting in a puppet. They were unsuccessful... as you can see now that the war has carried on for over 6 years.
(Plan B: balkanize the country) By doing so weaking it and also setting up military bases so that they could 1. Protect Israel and 2. Keep an eye on Iran and attack if they felt the need to do so. This is where the Kurds come in. They are being used to partition the country and divide it into statelets based on sectarian lines.
Here is the article I mentioned in Part A https://steemit.com/news/@sarahabed/the-decade-long-u-s-campaign-to-foment-syria-s-revolution-and-unseat-assad
The actions of the american government and your characterization of them are not what I'm questioning, they've been meddling in the affairs of my country since 1776 which is why we burned the Whitehouse (they painted it white to cover the scorch marks) in 1812!
What I'm questioning is your criticism of Israel's support of groups that you correctly label as (A) Marxist terrorists and (B) clerical-fascist terrorists when that is precisely what the Syrian government did when they supported PLO/fatah and hezbollah. Do you disagree with my characterization of all these groups as equivalent?