Very few people argue that intelligence is a "social construct", though the position taken by scientists and philosophers in the area is that race and gender are "social constructs"; that doesn't make them not real, though - but it does mean they're only about as real as money. A kind of objectivity obtained through many subjectivities.

"Extreme offense is usually taken when someone attempts to correlate intelligence with race"

As it should be, there's simply no data to back up claims like this.

But if you don't know that, intelligence being correlated with ethnicity is a plausible hypothesis. We shouldn't take offense when someone who doesn't know the data tries to correlate intelligence ethnicity purely because they are interested in biology. Which is of course probably not the motivation of most people who claim there's a correlation.

" intelligence being correlated with ethnicity is a plausible hypothesis"

No it's not, it's flat out racist.

It isn't. Judging someone by their ethnicity is.