Toi: They are minhagei shtus.
Careful; some of the minhagim, whose reasons no longer apply, are still binding on those who have the mesorah. For example, some don’t eat fish, because the fish used to be preserved in chometzdik alcohol. Although this is no longer the case, I know a family in which several members asked a shailah about this, each from a different rov, and all were told to keep the minhag.