That job creation might be in spite of government policies rather than because of those policies.
Presidents often get the credit or blame for economic developments for which they are not responsible.
Yes, that's always a possibility. However, you can think of the list as a reality check on the idea that it doesn't really matter who is president -- that presidential policies have little to do with socioeconomic trends, which are mostly driven by things outside their control. Well, if that were the case, then we'd expect results to be pretty random.... and they're not.
For example, picture if we flipped a coin 80 times. How big of a gap would we expect between the number of heads and the number of tails? It would be pretty small. Although it's theoretically possible to, say, flip 50 or more heads, it is extremely unlike (1.65% chance), and once you get into the range of say, 60 or more heads, it's absurdly unlikely to happen randomly (0.000429%). So, if you flipped a coin 80 times and saw that many heads, you'd be on firm ground to assume that it was a weighted coin, rather than a bizarre coincidence. If they offer you a wager on the 81st flip, you'd be wise to guess heads, because the evidence suggests it's not a random flip.
Well, in the same way, when you have Democratic eras outperforming Republican ones so often, over so long, across so many social and economic measures, it stops looking like random data. When they offer you a choice of a Republican or a Democratic president, you'd be wide to pick Democrat, because the evidence suggests you'll get better performance.