The word "catholic" (Greek: katholikos) means "universal" or "worldwide." In this sense, as in the Nicene Creed, all true Christians are "catholic," with a little "c."
"And he said unto them, Go ye into all the world, and preach the gospel to every creature." -- Mark 16:15
The patristic usage is in agreement with St. Ignatius. It is, indeed, related to "universal" but it is not reduced to commonality of basic Christian belief, as credal Protestants would have it. "Catholic", for example, means episcopal authority, common Eucharistic practice, valid sacraments, etc. It is universal in the sense that it is not local: ritual forms,devotions, vestments, languages might differ from one local Catholic Church to another, but the common theological and ecclesiological core remains.
The Eastern Orthodox use the term in its correct sense as well. Russian "sobornost" means something gathered together as to a Cathedral ("sobor" means both cathedral and gathering), and used where the Latins say "Catolica[m]".
It happens through history that a word gets reused with changes in meaning. Then you have a tension between older and newer meaning. It becomes problematic when some Protestant denominations reuse not just a word (like they reuse "church") but a formulaic prayer, the Creed, and then claim that it does not mean what the writer of the Creed, St. Athanasius meant.
I think those Protestant groups that do not say the Creed at all, or say something they themselves wrote instead are on firmer ground.
But it is not a big deal to me personally. I am not inclined to argue over words, same as whether "Roman" should necessarily be added in front of "Catholic". I only use it to draw a distinction between the Latin Church and other Catholic Churches, but others use it nearly all the time. It is not hard to disambiguate.