"Having just met you I can already tell nothing about you interests or excites me. I have trust issues and I fully expect you to leave me so in preparation for that I'm going to put up emotional walls and not invest myself too much in this relationship in case it fails."
There's a wide and opaque area between not being someone's clone and having nothing in common.
The parent meant, I assume, that they expressed the first one: that they don't currently know much about the other person's interests, and vice-versa.
That doesn't mean they won't learn about them. And, in fact, if the two people are compatible on a personality level, they'll likely turn out to enjoy similar interests—finding out about "things I liked but didn't know it."
But it does communicate something important: that if you're someone who isn't willing to learn about new things, and stretch your definition of "who you are" to encompass new things—i.e. to "invest yourself in the relationship"—then this won't work.
And that is an important thing to communicate, at some point (maybe not the first conversation, but at some point.) Some people really do just want a partner who likes "what they like", instead of a partner that will help them grow in directions they will enjoy only in retrospect.
That said and with a bit of tough love I really doubt they were incapable of understanding you. If they were, perhaps there's something you should change so they can understand you.
Offhand, your "I already know" remark comes off as putting up walls because you're afraid of being hurt. It's hard to learn about someone when they don't want you getting too close.
Can you identify what your common interests were in those relationships? What brought you together besides you both having equipment the other fancies? If there's a limited supply of answers, it's possible you really didn't have mutual interests or aspirations/life goals.
Long term they may have been doing you a favor.