It is a widely and repeatedly observed fact in social sciences that one's friend group is on average biased towards demographics similar to their own. This is true along a wide array of protected demographics relevant to hiring including age, race, gender, sexual orientation, etc. For some simple examples, a randomly selected gay person tends to have a significantly higher percentage of gay friends than a randomly selected straight person. Similarly, while 12% of the country is black, a randomly selected black person has way more than 12% black friends, whereas people of other ethnic groups on average have less than 12% black friends. It goes on and on.
People cluster by demographics. Good on you for being an exception, but the rule holds in general.