Nah, you can totally swing the blade open on a leatherman one-handed (use your thumb on the blade). There are some tools accessible from the outside of the leatherman that you don't need two hands to open but most of them are contained inside. It depends on which kind you get. My leatherman isn't going to help me hunt though I'll very much give you that. In fact on the page for the wingman it says everything can be opened and operated one-handed. I don't know it gets a little tough to get the interior tools out especially the correct interior tool (sometimes you end up pulling both out and then lowering the tool you don't need, this is really hard to explain without demonstrating) and some of the tools are stuff like "bottle opener" where yeah sure you can use it one-handed but your other hand's going to be busy) but anyway something to consider, i know for sure you don't need to use both hands to access all leatherman tools, given the right leatherman.
Ah okay. My claim was based on using my friend's Leatherman, and when you mention swinging it open I'm assuming my friend's was rusted or poorly maintained otherwise, because there was no swinging to be swung on that thing, more like wrenching to be wrenched.
Fun story the one time I thought I had killed myself on WD-40 it was trying to fix a friend's offbeat Leatherman that he had let rust into a very sorry state. For everyone who tells me not to use WD-40 on rust, yeah, okay, I know now guys. But did YOU know they have a national hotlife for WD-40 safety?
If my mom ever asks if I've ever gained anything from wasting time online, I'm finally prepared. That said, I respect your bravery in using WD-40 in the first place. I still struggle putting a sandwich together, I'm afraid the industrial-grade construction equipment will have to wait.