Why do I keep hearing how "it's galus etc" self defense doesn't apply in galus?
Let's take a step back and examine what Golus is, so maybe it will become obvious to you (and others).
Golus is a status of concealment. Yidden are called בני בכורי ישראל and were given many special gifts by Hashem. In a proper setting, Hashem's chosen people, firstborn nation, should be free of all problems, burdens and hindrances and occupied solely with learning Torah and keeping mitzvos. However, since we are in Golus, that is not the case (at least not in a revealed manner). Self-defense measures are appropriate, but putting too much emphasis on it is only burying ourselves deeper in a golus mindset, rather than focusing on a Geulah mindset of emphasizing good, and focusing on our true mission in this world. Putting
trust into self-defense and weapons seems to be distancing us even more from where our trust should be.