Smiley was wrong (spoilers)

Karla certainly did have human feelings regarding his daughter. He wanted her to be safe and well treated, treatment she could not get in the Soviet system.

On the other hand, Karla's "humanity" was also expressed by the brutal murders of the General and Otto, the attempted murder of Madame Ostrakova and the probable liquidation of Oleg Kirov. If this is moderation, I'll take vanilla.

Anything or anyone that got in Karla's way was to be eliminated, with prejudice.

Karla’s regard for his daughter’s wellbeing was his Achilles heel. As a brutal enforcer yet one more victim, according to Connie, was the girl’s mother. Packing her off to the gulag because she showed signs of straying from the cause, was his idea of a marital tiff, if I remember the phrase. But much more important is the devastating effect that the plan to compel Karla to cross over, had upon Smiley himself. Remember he had to be told, “George, you won!” and at the very end someone else said, “In all your life, George! Go well, you hear me.”