I agree @mumofoneAloneandwell being a SAHM is a job, in fact it's multiple jobs. Re, the women who go to paid employment as well, many of these will outsource to childminders, nannies, cleaners, laundry services, etc. The SAHM will do all the work these people do herself.
Working mums - especially full time ones - do NOT do a full time job- and 'everything else as well' (that a SAHM does.) They just don't.
And I say this as someone who has been a SAHM, a part time working mum, and a full time working mum.
SAHM is a little bit of a privilege but it's not an easy life for everyone, and it IS a job. (Indeed, multiple jobs as I said.) Frankly it's demeaning and insulting to say 'it's not a job.'