According to Statista, 133,294 rapes were reported in the United States in 2022, which includes attempts and assaults to commit rape. This figure does not include unforced statutory rape or other sex offenses. The rate of forcible rapes in the United States in 2022 was 40 per 100,000 people, which is slightly lower than the rate in 1990, when it was 41.2 per 100,000 people.
I'm not sure where the study you posted get the figure of 6 million from, but even if it is highly underreported, every assault does not result in pregnancy. That number needs some clarification for sure.
And just to be clear, there are not a bunch of people who don't support an abortion in that case, or the case of incest. This is just a way to justify having abortion for an "unwanted" pregnancy, as in I was not planning on it.