Agreed. There are a lot of different things that happened beginning at about the same time abortion was legalized -- widespread use of the Pill; increased sexual activity; wide availability of fast food; use of hormones in food production; and so on.
One interesting statistic is that average breast size has been increasing over time -- whether due to weight increases, or other factors, I don't know. But it might well be the case that simply having bigger breasts increases the chances of contracting breast cancer.
Any or all of them might combine to explain the increase in breast cancer.
One supposes it would be possible to better isolate the hypothesized link between abortion and breast cancer, by seeing if the breast cancer rate began to climb sooner, in states where abortion was legal prior to 1973.
that’s the problem, the msm won’t report on the facts that today, women in their 20’s get breast cancer while before roe, it was unheard of.