Most women’s social circles will not see men make any significant rightward shift in political opinion. Most peoples’ political opinions are fairly stable over time, and change slowly. Most people naturally spend time with people with similar political opinions. And if someone finds that they have significantly different political opinions than their peers, they will almost certainly keep it to themselves.

Right wing political spaces have a negative corrolation with female participation. The farther right a space is, the fewer women we expect to see there. And to the extent that there is a large rightward shift in men’s political positions, it is driven primarily by men who already leaned right. More left-leaning men, if they move right at all, would move right very minimally. The aggregate of minimal moves to the right across the bell curve would be noticeable at a statistical level, but would not be noticeable in most people’s actual social lives. Significant moves to the right would only be seen on the right wing side of the bell curve.

So if we accept your hypothesis, then we could also conclude that OP’s love interest is already involved in significanly right-wing spaces.

But the alternative conclusion, assuming your hypothesis is correct, is that OP’s love interest if more moderate/left wing (most women), but is chronically online and hears about men becoming more right wing.