I think being a SAHM in this situation is harder than a working mom IMO
I have done both so i am speaking from experience. Also before any of the trolls can talk out of their butts, we have never been on any P.A.. When I was a SAHM I never had a babysitter, ever, literally never and this went on for 3 years. I had to take a double stroller with hyper whining kids to the dentist, yes that was so fun trying to get shots in my gums while my kids are screaming, but I had to do what I had to do. Yet I am now a working mom as of the last 4 years and I think being a working mom (out of the home) is easier than being a SAHM with no breaks EVER. This does not include those who have help in that area, I have no comment on that as I have never had that so I don't know how that is. I only speak from my experience. No SAHM vs WM bashing here, just my opinion from my own experience!
Edit:The comparison isn't just working moms to SAHM's it's working moms who work outside of the home to SAHM's who NEVER have a break. That's the key factor, as in never have a babysitter (example, 3 straight years as in my case!).