You have to be in some serious denial or have complete lack of perspective to think having the means to bring a babysitter on your holidays is "solidly middle class"
There are literally dozens of comments elsewhere in this thread about how an au pair can be extremely affordable, borderline cheap. Feel free to read some of them, it's actually pretty enlightening if you're able to get over your unwarranted knee-jerk anger :)
You're entitled to believe that bringing a cheap babysitter on a family road trip a few times means we couldn't possibly have been middle class, but the assertion that I'm in denial or have a complete lack of perspective is uncalled for.