I think it might help to think about a lot of things a lot of people aren't comfortable talking about, but that we still think about -- or if we don't, we probably should: all kinds of bias, for instance, like racism, sexism, homophobia or biphobia, transphobia, xenophobia, ableism, fatphobia, classism, or the inequities all of these biases are based in or powered by. Sex, pretty much full stop: a lot of people aren't comfortable talking about any aspect of sex, not just masturbation. A lot of people are also massively conflict avoidant, and don't want to talk about things like conflict in their relationships, including their families. A lot of people are feelings-avoidant, and don't want to talk about their own or others' feelings.
I'm sorry you have felt scared to talk about masturbation, but know that it's certainly fine to talk about it here, no matter what you decide or want to actually do about it. In other words, even if you don't want to or feel the desire to do it, we can still talk about it.