You're comparing apples and oranges. Those conservative Christians who refused to do wedding stuff refused only to do wedding stuff; they were still completely willing to sell anything else to LGBT people like normal flower arrangements and normal bakery goods. Leftists completely refusing to serve conservatives at all is more like 1960s white Southerners completely refusing to serve black Southerners at all.

Also, when leftists completely refuse service to conservatives, as far as I know, conservatives haven’t yet responded by trying to sue the leftists in court to drive them into bankruptcy. But that’s what leftists do to conservatives who provide 99% of services but just refuse to do wedding stuff: bankrupt your political enemies! That’ll strengthen civility!