what you mean? synthesisers are software... I think the context is clear here and we're talking about software made for music, so the usage of patch is accurate. If author wanted to use "patch" to mean patching a file they would likely be specific or context could be inferred.
"A patch is data for modifying an existing software resource such as a program or a file"
Which is what patching synths/drum machines (and files) does.
The specific values of all of the settings on a synthesizer (including the inputs and outputs of any cables in a modular synth) have been referred to as a "patch" for a very long time. That's why the cables are known as "patch cables".
If you, for example, download sysex files for a DX7, they will often be referred to as "patches".
"A patch is data for modifying an existing software resource such as a program or a file"
Which is what patching synths/drum machines (and files) does.