A 401a/403b is a RETIREMENT plan, NOT a "rainy day fund". If "somewhat accessible" means raiding your retirement in order to pay for a new transmission, then no, I would not argue that is a stat worth "hating". Toss in taxes and a 10% early withdrawal penalty if you're under 59 1/2 and that makes things even stupider. All that assumes you even CAN access it early, as many plans have restrictions on early withdrawals too (and as mentioned, even if you can, it doesn't mean you should).
Having 6 months in savings isn't about how well it does for you on investment return anyway. It's about having a safety net that doesn't actively hurt you for using it. But hey, if you want to invest it in something performing better, that's a risk you might be willing to take. There's a reason why financial experts don't advise that though.
If you don't have liquid savings that are NOT earmarked for retirement, you can't "afford" a luxury item.
Again, it doesn't mean you can't have one, just that you can't "afford" one, which was the topic at hand...