As early as in 2012 when even official western reporting increasingly conceded that sectarian jihadists had „hijacked“ the Syrian „revolution“ many „experts“ expressed regret over the earlier non-intervention of western military powers in favor of the Syrian rebels.
The implicit argument that before it´s radicalization the „uprising“ deserved western support is flawed in many instances:
1. Despite often repeated but misleading claims about the „revolution“ having been peaceful „at least for 6 months“ (or one year according to others) it was always disputed whether not major parts of the uprising were armed, violent and sectarian from the very beginning. Contrary to the former romanticization of the insurgency deadly attacks and systematic ambushes on police and army happened from day one.
2. After the Libya experience it was clear that Russia would not accept a UN resolution allowing western states to go for their much desired „regime change“ under the pretext of „responsibility to protect“.
3. There was never a Syrian opposition with a broad popular support base inside of the country. After the experience with Ahmad Chalabi in Iraq probably even western regime change proponents were suspicious of similar claims by Syrian exile opposition members.
4. There was no truly deployable opposition ground force to bank on. The „Free Syrian Army“ never had any command and control structure, cohesion, unified leadership or infrastructure. It was never more than a name, but a disconnected conglomeration of undisciplined local militias. By contrast, in all the year when various rebel factions tore eachother apart and entered coalitions even with Isis and Al Qaeda (Al Nusrah) just to abandon them or be abandoned, fought and disarmed by former allies, the Syrian army and it´s allies never had any internal fighting.
5. Why should external powers intervene in a civil war, bring about the defeat of the stronger side and empower forces that they don´t know and whose actions they probably cannot predict and contain?
It is very likely that despite much rhetoric about supposedly regretting the lack of earlier action on behalf of the Syrian rebels and against the Syrian government, the army leaderships and secret services of the western powers had serious and legitimate concerns about bringing to power sectarian and highly violent radicals.