I mean, whatever you think of WAR, Gio was #22 in MLB last year in WAR. Guy just has to eat crap sandwiches from this fanbase though.
I'm mindfacting, but it seems like the typical Gio start is 5 IP, 90 pitches, 5 walks, 3 earned runs. I think what frustrates people so much is how rarely he pitches deep into games.
OK, I looked it up - averaging around 30-32 starts a year he's only hit 200 IP twice, with a career high of 202. He's averaging around 3.5 BB/9 since coming here, with a RA9opp north of 4. Only 52% of his starts this year were quality starts, averaging about 100 pitches in 6 innings of work.
That's the crux of it, he's not pitching deep into games and thus is putting a lot of stress on the bullpen.