“Charity” shops in my area are for profit businesses. Sure someone is getting a small donation, but their board members pull large salaries. Never mind their free inventory and usually underpaid labor.
It's a common complaint that donations should not be used to pay salaries, but the important question should be how much leverage those paid staff can extract out your donation. Skilled people usually don't want to work for free, but they can magnify a donation by reaching more potential donors via advertising, more appealing shops, etc.