Stalin was a communist revolutionary who played an integral role in the creation of the USSR. Putin is a liberal counterrevolutionary, who is partly responsible for hypercapitalist modern Russia, the two are not comparable at all.
If by “he sure is like stalin”, you mean he employs violence to maintain and consolidate power, that’s every state ever, that’s kinda how states work.
Being an extremist means having any more nuanced view than “stalin just loved doing evil things for absolutely no reason”