The claim is not supported by the evidence. Research on obesity in men consistently shows increased conversion of androgens into estradiol, and sometimes estrone, in adipose tissue; it does not show that obesity causes excess estriol. Because estriol is a distinct estrogen and the cited studies do not document elevated estriol in obese men, the claim is false as written.
Caveats
The claim conflates estriol with other estrogens, especially estradiol; these are not interchangeable.
Most strong sources here discuss obesity-related increases in estradiol or estrone, not estriol.
Some lower-quality or non-primary sources use broad language about “high estrogen,” which can mislead readers about which hormone was actually measured.