They are left leaning according to mediabiasfactcheck and gender discrimination is a heavily politicized topic. Their agenda is also about clicks; gender discrimination claims will generate more clicks than a science article
They might be right, I'm just not inclined to belive any of those sites.
Then their is wiki - a crowd-sourced perspective: "the paper's readership is generally on the mainstream left of British political opinion, and its reputation as a platform for liberal and left-wing editorial has led to the use of the "Guardian reader" and "Guardianista" as often-pejorative epithets for those of left-leaning or "politically correct" tendencies."
https://en.wikipedia.org/wiki/The_Guardian
But this whole right/left labeling has got silly and used as a means to label and dismiss the subject/debate at hand. It's a whole sliding scale and as always it is the extreme edges of both the left and the right that are the real issue. But alas many will label something left or right and project that edge-case upon all on the divide, however close to the center they may be.