Why did hard line communist leaders resent Mikhail Gorbachev?

The Communist party took control over the soviet union to try and stop Gorbachevs "perestroika" program.

Gorbachev's call for major political reforms as well as economic ... As if to counter hard-line statements in the region, a senior Hungarian Communist official issued a ... "I do not think the turn in the Soviet Union was too sharp," he added