Ryan Fazio visited New Haven Thursday not to tour Yale, but to tax it. In the “Dateline” interview, Fazio, a 36-year-old state senator from Greenwich, said that if elected he would pursue having Yale’s tax-exempt property become taxable. In the past Yale has framed efforts to tax its property as an attack on tax exemptions for all nonprofits including small churches. He characterized the Yale/hospital proposal as part of a broader “affordability” campaign theme centered on lowering property taxes and electricity costs. Trains meeting at the station: Fazio and State Comptroller Sean Scanlon cross paths at WNHH FM Thursday between successive “Dateline” interviews.