Undergraduate Math degrees should cover a much wider range of mathematical topics. Many schools don’t have enough students to offer many courses exclusively for Majors so that often blurs the lines.

Topology a a few others may make the cut, but it’s much easier to share requirements with other programs so a Math degree may include courses that are required or attract students from a Physics, CS, Engineering, Music, Economics, Chemistry, Philosophy, History, etc degrees.

Depending on how you set it up “History of Mathematics” could attract students from several different majors which means you can offer it more often etc.