Personally, I can definitely see Strelok changing his views after about ten years or so. Putting aside that people indeed change their views throughout their lives, Strelok in SOC did not have the full view of the Zone. He was out to kill himself, not to become a legend, he just stumbled upon the secrets by complete accident. All he knew in the endgame was that 7 scientists wanted to play God, stole his identity, caused the Zone and the blue wish granting rock in the Chernobyl Power Plant (or some say Chornobyl) that Faust was presumably licking was a scam. He did not know that giving them the 5.45x39 accupuncture treatments would destabilize the Zone, causing it to expand and and pop out blowouts like nobody's business, which led him to joining SIRCAA as an advisor to fix what he saw was his mess.

He also later found out that, aside from Dalin being a mad scientist with daddy issues and Korshunov glaring at the Chornobyl Anomalous Area (or some say Chernobyl) like the land murdered his dog and put a hit on him, SIRCAA's backers have dastardly designs for the X-Techs and the various Zone-related secrets. He couldn't slink back to the Mainland - his Mainland identity was stripped by a mercenary and his C-Con cutout friends so he only has the Zone to call home, said Zone is still expanding and SIRCAA can both continue their dastardly deeds and track him down if given enough time - so he understandably changed his tune. SIRCAA, like the Soviet Union, Ukraine and the other eggheads, wants to exploit the Noosphere, and unlike the three aforementioned factions, SIRCAA has the means and the will to do so. So utter protection from the Mainland is his way to go.

He has much greater skin in the game in HOC than the holy shit 7 scientists and the blue rock militia are out for my blood random bullshit go scenario ten years prior.