It's true that one half of people literally has less-than-average intelligence...
Depends on the distribution. And which average.
IQ is distributed normally.
That's begging the question.
what do you mean?
The definition of IQ says that it assumes a normal distribution, with half either side of the mean. To use the definition of IQ as a justification for the statement "half of all people have less than average intelligence" assumes that the distribution of intelligence matches the distribution of IQ.
If defined traditionally (from the Greek), it's the literal truth.