They will let Hunter do a public hearing, once Hunter does a closed door deposition hearing first. Hunter's lawyer Abbe Lowell, wants a public hearing because the questions are only limited to 5 minutes, for each committee member. Whereas with a closed door hearing, they can question Hunter all day, if they want to!!
No, I think the real reason they want to do it in camera is because they can then lie and twist what is said and selectively release transcripts to paint their false narrative of corruption. Let's face, Comer and company have about as much evidence that Joe did something wrong as there is physical evidence of the loch Ness monster or big foot. Lots of blurry photos that could've be doctored, a lot of discredited people claiming to see something, but nothing tangible.
And, let me say this, if they can find legit evidence, then I am all for impeachment. But the reality here is they got nothing. They talk a big game, makes damning accusations, but when it comes time to actually pony up the evidence....bupkis... And I don't think that's going to chance here. I mean, if there was evidence, why aren't more GOP members calling it out? Hell, there is a good chance that if it comes to a vote, some GOP members might vote against it or not at all...Imagine the embracement of Comer and Jordan then....
Edit to add:
Also, I don't think Hunter will testify anyways. This is just calling Comer's bluff. What benefit will it give Hunter, especially since he is still facing criminal prosecution. Plus, Gym Jordan and the GOP set a precedent during the January 6th investigation about ignoring subpoenas, so we'll see how it all shakes out.