The Carbon Tax is controversial because fighting climate change has become a polarized topic. Outright denying climate change is almost political suicide for most politicians, so they do the next best thing and criticize any policy made to do anything about it.

The Carbon Tax is controversial because it is more socially acceptable for people to say a solution won’t work than just admit they don’t care about the problem enough to do anything about it.

https://vipfinance.ca/what-is-the-carbon-tax-and-how-does-it-work/