Furthermore, professional armies are much more reactionary/apolitical in nature.
Active duty force - yes, there’s a clear reason for that - material interests (paycheck). Disenchanted and disenfranchised veterans - not as much, perhaps.
There’s another thing worth mentioning - the dichotomy of “professional” vs “conscription” is not as either/or as one may suggest, rather it’s become and/both, dialectics-style. Take Russia, for example: before Wagner was incorporated into the AF, they had all three - conscripts, professional/voluntary and mercs. The US is to be noted too - the Blackwater PMC has at least 110,000 soldiers, perhaps more.
I would like to expand upon this point and say that “a soldier with the wrong kind of political or ideological education is most probably a criminal”. Conscription or not. Just take a look at the Ukrainian army - it isn’t hard to find people with swastikas on their uniform. And, they are definitely not unhappy about being criminals. Just like the original Nazis they glorify.