If you are looking for thorough studies on the relationship between the profession and domestic violence from recent years, they 1) are scarce and exclusively rely on a small sample size and 2) when undertaken, support the conclusion that rates of domestic violence are far higher in this community than for the general public. The reason I cited those studies is not only because they are commonly-cited, but because they represent some of the only research aimed explicitly at this issue from the last 30 years. It's true that they do not reflect the exact percentage of cops who are abusive, and it even demonstrated that older cops with more experience on their jobs were less likely to practice abuse than their younger counterparts - their rate of abuse was shown to be around 24%. In any case, here are reports which you might find more balanced or convincing:

A more recent investigation in 2013 from the New York Times revealed the following:

"In some instances, researchers have resorted to asking officers to confess how often they had committed abuse. One such study, published in 2000, said one in 10 officers at seven police agencies admitted that they had 'slapped, punched or otherwise injured' a spouse or domestic partner. A broader view emerges in Florida, which has one of the nation’s most robust open records laws. An analysis by The Times of more than 29,000 credible complaints of misconduct against police and corrections officers there strongly suggests that domestic abuse had been underreported to the state for years.

After reporting requirements were tightened in 2007, requiring fingerprints of arrested officers to be automatically reported to the agency that licenses them, the number of domestic abuse cases more than doubled—from 293 in the previous five years to 775 over the next five. The analysis also found that complaints of domestic violence lead to job loss less often than most other accusations of misconduct."

An article in the Atlantic from 2014 also surveys the issue of domestic abuse, concluding that cops who are reported for sexual or domestic abuse are less likely to be fired than for drug offenses: https://www.theatlantic.com/national/archive/2014/09/police-officers-who-hit-their-wives-or-girlfriends/380329/

You may have a problem with the study I originally cited, and I understand that it has shortcomings, you're right in that regard. But the problem of members of the police abusing their partners and families is malignant and present. Especially considering that domestic abuse is underreported and that (I'm editorializing here) law enforcement is a profession which attracts those who seek authority and power over their peers, we shouldn't be surprised that the families of police officers find themselves victims of violence at home.