Whether something "Matters" is a value judgement, not a provable or disprovable fact. If we were all going to be honest, each of us would say "Few lives matter" since who matters to each of us is a relatively small circle: friends, family, and perhaps favorite celebrities (entertainer/sports star/politician/etc) for some. Really and truly, expressing "personal importance" in saying those outside that circle lives "mattered" is just pandering and virtue signaling, just trying to medal in the caring olympics.