I have no association with the plugin, but I think I might be able to contribute to answering your question in the proper context.
Unfortunately, incorrect use of the terms “hacking” or “hacker” has so diluted their true meaning, that they are frequently – if not almost always – immediately assumed (by the “normal user”) to be synonymous for actions that disrupt, deface, circumvent, or gain unauthorized use of and access to, software and applications. I think that’s technically referred to as “cracking”, rather than hacking.
I think – meaning just my personal interpretation – that the intention of the term “Hackable” in the plugin description refers to the ability of the plugin to be modified, molded, customized, edited and easily adapted by the end user to suit their needs.
But you’re probably right on point. I can certainly see where interpretation of the wording would definitely depend on your mindset. An unintended double-meaning in this case, perhaps. Certainly made me smile a little when I read it!