There is actually several older papers showing that as men get older, bioavailable estrogens drop. That has been known for a while. So this new result is not surprising.
The internet meme that estrogen goes up with age is surprisingly hard to get rid of, though, even though it is not true. (It may be true in a particular individual, but not for the average male.) I guess the lesson is to be careful with bro-science "consensus."