Yeah, that was my thought as well. How the hell does that work?

It's about turnout.

For example, Obama wins in 2008 and 2012 with majorities in the popular vote. So, are there more Democrats or Republicans?

There are still more Republicans. Obama won the popular vote in 08' because a lot of them didn't show up to vote for McCain. That happened again in 12'.

Just because the Dems generally turn out in bigger numbers for Elections, doesn't make them the majority in the country. Republicans don't have to show up in big numbers. The system is structured to give them huge advantages.

Republicans win even if fewer of them show up to vote.

Whites make up about 66% of the voting pool but only about 60% of the overall population. That's because old White people vote in bigger numbers than any group except Black Women.

Up until recently, if a Republican got a big turnout of White voters they would win. Trump got the biggest turnout of White voters ever in history.

They scoured the country for pockets of Whites who don't typically vote, like the Amish, and tried to recruit them into voting Republican. FYI, the Amish now vote Republican.

Even with that massive turnout Trump got only 49% of the popular vote. Biden got 51%. Biden won by 8 million votes.

Trump's vote looks like this:
42% White (2 out of 3 Whites)
1% Black (hasn't changed in 30 years)
6% Hispanic (increased 2%)

Biden's vote breaks down as:
24% White (2% of that is crossover votes from RINO Republicans who would not vote for Trump)
12% Hispanic (2 out of 3)
10% Black (9 out of 10)
5% APII (statistically all of them)

Since 1992 when Clinton got 43% in a maximum effort election Democrats have increased their share of the electorate by about 8%, maybe.

There is this meme that since Dems consistently "win the popular vote" in National Elections they must be the majority in the country. It's not true. They just show up in bigger numbers to vote.

And still lose.