Fearless only when their fearlessness supports their viewpoint. They wouldn’t dare look into issues that go against their bias. According to the Guardian, Brexit is 100% bad, when in fact, the issues surrounding Brexit are in shades of grey. It’s not particularly courageous to write articles with which you already support. Courage would be writing articles that challenge their widely held assumptions.
While not the majority of their content, they have had a number of pro-brexit opinion pieces and pro-WAB articles from people across the 'left' brexit spectrum and even some centre/right writers.
Their editorial is pretty evenly split. A lot of readers who are remainer complain about pro brexit positions. The labour party is split. Owen Jones (as an example) and Martin Kettle) certainly don't make your case.
Basically, I think you're factually wrong. You're reading selectively if you believe this about the graun