We are back to this stupid argument were idiots argue their seat of the pants understanding of how the law works applies rather than the law as it really is.
1. The Bill Clinton impeachment was started solely upon the hearsay testimony of Linda Tripp. If that is your theory, Bill Clinton is owed a formal apology from the U.S. Government, reimbursement of his legal fees, and since it is so wrong on every count as you put it, Mitch McConnell and Lindsey Graham have to immediately resign as according to you they committed this very wrongful act.
2. The state department IG said the whistleblower account contains both first hand and second-hand knowledge. That makes your argument bogus.
3. The call summary was an official record of the government and not second-hand information.
4. Text messages on government-issued phones are not second-hand information. They are official records.
5. When Trump goes on TV and tells China and Ukraine to investigate Biden that isn't second-hand information.
6. When Rudee or any other member of the administration goes on TV and admits to doing something that statement is admissible.
Hearsay is frequently used in both Federal and State Courts. Matlock, if you want to talk intelligently about this issue, I suggest you read the Federal Rules of Evidence that explain what is and is not hearsay and detail all the exceptions to the hearsay rule. I have decided to kindly provide them for you here.