I agree that people clearly don't use critical thinking 100% of the time and are easily influenced.
But you're basically arguing for not criticizing the status quo.
Many social improvements have been attained by "attacking the foundations of society". How would you like living under some absolute monarchy? How do you think gay people would like to live in a church-run society like 500 years ago?
"But you're basically arguing for not criticizing the status quo.", but that wasn't what was argued ("You should be able to insult and criticise the Prime Minister."), but more your interpretation of what was said. You're making a strawman argument.