I am not against having an inquiry on if Trump should be impeached. This should be done first because you want to investigate the matter before jumping to conclusions. There are several reasons why you'd want to investigate:
- First, Trump used words like "fight like Hell". That can be taken both literally and non-literally. How do we know which sense he intended if we don't look into his intent? Plenty of politicians from both sides have used similar language, but we don't impeach them nor automatically suggest that they are inciting or trying to incite violence. Also should Trump be blamed if he intended it to be non-literal but some protestors took it to be literal? That's certainly possible given the fact that not all protestors entered the US Capitol.
- There is growing evidence that the attack on the US Capitol was planned. If the attack was planned before Trump's rally then some of these pro-Trump protestors already had it in their mind to attack before listening to Trump's speech. Perhaps we can investigate if Trump played a role in that planning. We should know that before trying to impeach him.
- Another point that was brought up mostly by Democrats is that Trump did nothing to stop the attack. That should also be investigated. Trump released a video during the attack calling for protestors to stop their attack and leave. Perhaps he could've done more, Perhaps the FBI and US Capitol police could've done more given the fact they had some information on threats prior to the attack.
Without a proper investigation, especially letting the other side (Trump and his team) give a statement, then the impeachment is just simply a rush to judgement.