Almost all the O'Connell Ave. have gardens deep enough to accommodate at least one car. On street car parking is a privilege and the needs of the great number of people should take priority. It's an absolute mess around The Mount when the schools are open. You could walk it faster between the monument and Punches Cross.
Schools can have that effect right enough, and not just at the Mount. I can think of some stretches on that bus route where a fair amount of demolition would be required to get cars off the street. Many of those houses are old (and large)and pre-date household requirements for more than one car. Surely that opposition is for very real and practical domestic reasons rather than any aversion to a bus lane.