They push a center-right president onto the stage
Like, 90% of the US Senate is center-right or worse. You're in a country that is governed overwhelmingly to the right of the popular political view. I don't think the VP pick is going to meaningfully shift any of that. Running Walz as your VP isn't going to turn the US Senate into the Minnesota Governor's Mansion.
How about you offer actual progressives some goddamn enticement for once and offer it to Jamaal Bowman, who the Dems primaried in favor of a genocidal AIPAC stooge?
Because the US has a huge geopolitical strategic interest in staying friendly with Israel and a vanishingly small interest in cultivating support among progressive New Yorkers.