It's because he was lead investigator who took down the 2011 Russian spy ring in the operation known as "Ghost Stories".
https://www.fbi.gov/news/stories/ope...ssian-spy-case
He and his agents took down 10 Russian spies who tried to set up shop here in the US. This is not fake news, not TV stores but it happened and Russians were caught red handed trying to infiltrate our political system.
It's fair to say the Russians not only have corrupted Trump but likely have many assets with in the GOP. It's pretty much a given when looking at their actions of many House members who are trying to sabotage the FBI investigation.
They aren't doing it just to protect Trump, but also their own asses.
The entire objective of the Russian spy ring was to gain influence in our political system. It's safe to say they found many willing participants with-in the GOP power structure.
"The SVR was in it for the long haul. The illegals were content to wait decades to obtain their objective, which was to develop sources of information in U.S. policymaking circles.
Although they didn’t achieve that objective, the agent said, “without us there to stop them, given enough time they would have eventually become successful.”
It's a given they didn't stop trying or had more than one operation going. The only reason Republicans are this content with ignoring Russian spying and try to sabotage the FBI is because they have been corrupted and are traitors.
Peter Strzok was the head of that investigation..