True, but NONE of that is required to open an investigation.
The Clean Hands doctrine applies mostly to Contract Law and Civil Law.
https://www.law.cornell.edu/wex/clean-hands_doctrine
Clean-hands Doctrine
The principle that someone who violates equitable norms cannot then seek equitable relief or claim a defense based in the law of equity. A party who has violated an equitable principle, such as good faith, is described as having "unclean hands."
It is not applied in Criminal or Federal investigations.. its a defence, in a court of Law
The Feds have their own organisations for badly behaving prosecutors and investigators - the FBI have the OPR, prosecutors come under prosecutorial misconduct laws with punishments administered by the relevant Bar Association, unless the misconduct was criminal.
So long as warrants are obtained before surveillance takes place (and as far as we know, they were at every stage of the investigation) then the surveillance is legal.
If the investigators had every reason to believe that the original premise was a valid one, then they have acted in good faith, even if the premise later turns out to be sketchy... in other words, once the investigation has been started, and criminal acts have been found, all bets are off. Pandora's box has been opened, and it stays open.
Of course, The Right would have you believe that the whole investigation was based on the Steele Dossier, when in fact it was just ONE of the things that led to it. They also want you to believe that it is phoney document. Well, for an alleged phoney document, it sure is hard to explain how it got everything verifiable right with such stunning accuracy. The only things in the dossier that haven't been verified are those thing that are not able to be verified, because the Russian aren't telling, and Trump family and their sycophantic hangers on have lied about them.
1. Contacts between Trump's team and Russians
(true)
2. Russian meddling in the 2016 election
(true)
3. Trump's real estate dealings in Russia
(true)
4. Potential Russian leverage on Trump, i.e. kompromat
(suspected but can't be verified)
5. Michael Cohen's alleged trip to Prague
(suspected but can't be verified)*
6. Michael Flynn's paid trip to Moscow
(true)
7. Carter Page's meetings with Russians
(true)
8. Russia wanted to help Trump win the election
(true)
9. Russia has extensive program of state-sponsored offensive cyberoperations.
(true)
10. Kremlin behind recent hacking of DNC e-mails
(true)
11. There is a close relationship between Putin and Russia’s largest commercial bank
(true)
* Cohen denies ever being there, but its known for a fact that his phone was pinged off a celltower in Prague.
If I was a betting man, I would bet that there are a whole lot more confirmations of the remaining unverfied memos in the Steel Dossier buried under those redactions in the Mueller Report.
Let me ask you this.
You are being investigated for a murder, and it absolutely was not you. You KNOW it wasn't you. You know exactly what you were doing at the time the victim was murdered, but you have no way to prove it; no witnesses to you whereabouts, you don't appear in any streetcams in some other area, you didn't receive or make any phone calls, i.e. you have no alibi for the time of the murder. This is an injustice, right? You know you didn't do it, but the Police are investigating you and you are their prime suspect!
Are you allowed to obstruct that injustice?
Are you allowed to ask people you know on the Police force to keep you informed about their investigation.
Are you allowed to get someone to lie for you to give you an alibi?
Are you allowed to try to get your uncle, the Police Commissioner, to shut the investigation down?
If you answer "YES" then we have a problem, because you will have just thrown the Rule of Llaw out the window, and everyone here will know there is no point debating with you
If you answer "NO" then you need to explain why Trump is allowed to break the law to protect himself from investigation, but you are not.