"I make no pretense..." means "I don't claim to..." For example, "I make no pretense at being an bitcoin expert" means "I don't claim to be a bitcoin expert."
So here's some more helpful analysis:
"I don't claim to despise BTC" means I like it.
"I don't claim to not despise BTC" means I don't like it.
Thus, "I make no pretense to not despise BTC" means I don't like it.