I am fascinated by these types of comments.
Why are you amazed? Does it bother you that people are doing (what you judge to be) something wrong?
There are hundreds of thousands of assimilated jews. What bothers you more the latecomers or these people intermarrying and not keeping torah?
My speculation is that the latter doesnt bother you so much bec u dont feel that they should be doing better. However you have concluded (perhaps erroneously) that these latecomers should know better.
Just my two cents – feel free to disasgree