There is a fundamental difference between empathy and solidarity. Empathy is overrated. You can't reliably run a society on it.

A person can be completely empathetic but effectively do nothing. On the other hand, we can be solidaric with people we do not necessarily empathise with. (much of what Camus writes is on this theme).

Human empathy and its inverse are far too easy to manipulate. Empathy is too often used to fuel in-group/out-group thinking. Solidarity stems from fundamental understanding so is much less prone to these types of easy manipulations.