With my life experience thus far, I see you've hit the nail on the head. As a young lady who has chosen not to have children, I get all sorts of nonsense from other women. The major theme in these cases appears to be the fact that they did not make the best choices or regret some of their own (major) choices. Perhaps they want an opportunity back or know they can't have it back and lash out at those who are the way they wanted to be or lash out at women who are doing things they wish they were able to. Unfortunately, some make the choice to let this resentment and even jealousy be well known to their detriment and sometimes the detriment of others.
Often, these same women cannot relate to things that are important to me and they come across as being stuck in a time warp when they make this position clear. I have taken a lot of abuse just to avoid confrontations with people over this stupidity. Perhaps some of the offenders sense this and delight in putting me down to feel better about themselves knowing they won't have immediate reprimand from me? I just try to separate myself from these types the second that they act this way. I have enough things to worry about, not grown women with self esteem issues and their attempts to project these things onto those around them.
Sorry to go on and on, but my life experience shows truth to your question.