Its entirely possibly, and likely this latest atrocity is the work of Assad or forces nominally under his control. There's also some possibility it wasnt that cant be entirely discounted.
The question is, other than lambasting Labour for issuing near identical statements of condemnation as those noted appeasers, the US & UK governments, what course of action is being proposed here?
Israel is taking the opportunity to widen their strikes against Iran at a time when their massacre of civilians in Gaza could spark retaliation from Lebanese Hezbollah forces. The Russians are already smarting from US airstrikes and sanctions and the Salisbury nerve attack which is being played as dirty propoganda (with some justification) in Russia. We have an already dangerous breakdown in cold war failsafes, communications and heightened tensions between Russia and the West - and look at the personnel involved, Trump, Bolton, Netanyahu, Putin, Assad, Macron... a cast of venal grotesques, macabre thugs and idiots.
How precisely do you think this will pan out if the conflict widens as the UN is already warning it could? This is an exceptionally dangerous situation.