Because government making decision based on morality is slippery slope as morality is very subjective and varies with people, race and religion. Also is not Republican the party which advocates small government?
It's easiest to see how useless the "slippery slope" concept is when noticing that it can be applied to absolute everything:
"if I start by feeding my own kids, I will soon have every needy kid at my door, asking for food"
"If we start to expect politicians not to be murders, a parking ticket will soon be disqualifying"
etc. etc.
Specifically here: government makes decisions based on morality all the time. I'd argue every single decision by the executive, legislative, and judicial branch is based on morality. It's obvious for the criminal justice system. For everything else, like deciding between different uses of tax money (aircraft carrier or social housing), making decisions requires some sort of function to optimize, and that function can ultimately only rest on morality.
But I agree, government forcing a company to do something isn’t particularly in line with Republican ideas and it’s hypocritical in the context of limited government.