Well, depending on how the service marketed itself, I don't think there's anything wrong with doing that. If people want to use an internet dating site to find someone they are happy with, and if they are more likely to be happy with someone similar to them, then you are providing what they asked for. If they find they aren't happy with similar people, I'm sure there are other dating services which deliver that specifically.
It's not our job and it's not right to force our values on others because we think it will make them better people when that's not what they asked for. That said, I think it would be different if a news organization was doing the equivalent, and serving items that confirmed prior ideas. the difference there is that in one case they are asking to be happy, and in the other they are asking to be informed. This does of course assume people actually want to be informed and news isn't just an entertainment medium for the customer as well now...
This was my line of reasoning as well. You can't tailor an entire business around the 1% of cases where a sheep herder in Asia and a multimillionaire from Texas really hit it off.
In this example it sounds like the app was making assumptions and pre-segregating matches based on implied attributes rather than specified preferences.
So even though a user might only say "show me matches between 18-35 years old" the app would apply additional filtering based on the user's supplied attributes in an effort to improve "relevance".
I'm not saying you're wrong, or that this was wrong/right but I did want to clarify what the OP seemed to be saying.
It's not our job and it's not right to force our values on others because we think it will make them better people when that's not what they asked for. That said, I think it would be different if a news organization was doing the equivalent, and serving items that confirmed prior ideas. the difference there is that in one case they are asking to be happy, and in the other they are asking to be informed. This does of course assume people actually want to be informed and news isn't just an entertainment medium for the customer as well now...