Unlike the usual Bettridge's law, the answer to the headline is only a qualified "No".
It is a "So is all other cancers!", which is pretty bad news for folks who are young and healthy right now.
EDIT: having thought that over a third time, I am not sure it makes any sense.
That being said, I can see a few plausible biases (though none of them explain the scale of the increase IMO):
1. CRC risk is correlated with some previously fatal, but now curable disease. The mechanism would be that your high-risk CRC patients would die due to yellow fever or something in 1970, meaning they don't have the chance to get CRC. The important thing is that it would have to "artificially" remove high-risk patients from the age group, but not low risk patients.
2. CRC risk is noticeably higher at 24 than it is at 20, and all-other-cause mortality is significantly lower today. That would lead to a higher proportion of 24-year-old "years" in the calculation.
3. People used to die of CRC before it was caught, which caused it to not be recorded as a cancer incidence.
1 seems unlikely, and even if true shouldn't make a big difference. 2 seems the most possible, but still unlikely to make a huge difference. I don't know enough about how they determine cause of death to know if 3 is a possible outcome.
The overall age-adjusted cancer rate has been going down, and the death rate even more so.
https://en.wikipedia.org/wiki/Betteridge%27s_law_of_headline...