Sure, lab leak could be true and with all the available evidence, could very well be true but the confirmation of of it being true may have more far reaching domestic and geopolitical ramifications that may do more harm than good.
It seems like there's some game theory going on within the political sphere of many western governments in that increasing anti-China sentiment by confirming lab leak could further put us down the path to an eventual confrontation (read: war) with China, in which we lose a lot more.
The only thing we gain by admitting to lab leak is the truth but is the truth (that we've pretty much deduced at this point) worth worsening relations not only politically but gives anti-Chinese factions in the west more evidence as a prelude to war?