... why People typically use bitcoin mixers to mask any previous "questionable" transactions from the bitcoin that they are likely cashing out in their real name.
why didn't you post your real name, address and bank account balance here on the forum? is your actions "questionable" because you wanted to keep your privacy?
that is the same with bitcoin mixing. bitcoin is not anonymous and many don't want any Joe on the internet snoop around in their wallets to see how much bitcoin they own, where they spend it,... so they use mixers.