It could easily be said to not believe too much coming out of an anonymous deep state whistle blower with 2nd and 3rd hand information. Also Shokin's comments seem to at least corroborate Biden's own actual admission that he threatened to withhold a billion US dollars from Ukraine if he wasn't fired. "Well son of a B...., he was fired" -Joe Biden
Just because the probe into Burisma might have been dormant doesn't absolve Biden of any wrong doing, he still wanted them to back off of any investigation into his son's involvement. The Obama administration always has and apparently always will get a free pass.
As
@Avalanche stated Trump did not say "go after Biden", did he mention his name yes but to look into corruption. I'd think we would want our leaders to look into corruption that involved American citizens with foreign identities. I mean we just wasted 2 years of looking into possible collusion but they seems ok to do because it's Trump. Mind you I'm no big Trump fan, I've said this in previous post but I also don't let my personal feelings toward one candidate or another cloud my observations.
What Trump really wants them to look into is the whole corruption scandal surrounding the 2016 election and as it relates to those in the DNC. This whole impeachment process has tons to do with the fact that somebody was getting very warm/close to uncovering the real corruption that occurred (you remember, bought and paid for fake dossier that started this whole collusion mess in the first place) and names coming out. I mean why else did this whistleblower meet with Schiff aides priory to actually filing the complaint?