You realised, you mean you didn't know before you started reading it? I'm almost 75 and I know it has always been moderately left wing.
It's a good newspaper though, far better than many. However I do question articles like the one posed here. I don't buy a paper now but do read some of each online. I've noticed a tendency for the broadsheets to emulate the tabloids a bit these days, trying to attract new readers I suppose. Thd Indy is the worst for that by far but they all seem to have a go. It must be something to do with the decline in sales, most people get their news online.