You don't love them just because they're family.
I spoke to a woman this morning who wants to get the cats she has been feeding sterilising, because one of the lots of kittens were taken away by pest control. One of the reasons is that she and her friend feed the cats upstairs - her friend has a makeshift home for them on the second floor, she had another on the 8th floor. She kept insisting it's not safe for the kittens to be in the void deck when they are young. Certainly there is a risk of leaving them in the void deck, but leaving them upstairs is infinitely worse. In both cases, people complained of the cats defecating - and the woman said that her friend cleaned up, but couldn't do it around the clock. This means that people ARE going to complain - and they did in this case - and the cats get rounded up.
She also mentioned what a few people have mentioned - that cats should have family because they especially love genetically related cats. As far as I have seen, this is not true at all - I have a pair of siblings that absolutely hate each other, and other cats which are not related which bond for life. I've seen this in other cats too - it doesn't mean cats that are related aren't necessarily very loving, but it also doesn't mean they will be friendly just because they're related. I personally think it has to do with temperament rather than blood. I would think it is the same as with people :)