That certainly doesn't seem to outlaw people casting votes for independence.
The constitution merely invalidates the referendum, it doesn't actually make it illegal. However, obviously it's criminal to spend public money on organizing an unrecognized referendum.
Given that the referendum itself isn't criminalized, it seems ridiculous to argue that simply by participating one would be violating the law.
It's also important to keep in mind that even the Spanish government has not attempted to argue that it's illegal to vote. This is just a meme being spread on online forums by people who mostly don't even understand the difference between the constitution and the criminal law.
No, I'm not. I've made an effort to read and understand the relevant law to the best of my ability. If someone knows more I'd welcome any further information.
>I don't know whether merely voting is illegal or not at the level of individual people.
My understanding is that the constitution simply invalidates the referendum, and I'm certain it doesn't explicitly criminalize it.
Keep in mind that even Madrid has not been pushing any claims that simply voting would be illegal.
>But the issue seems largely moot, as it wouldn't be feasible to prosecute individual people for voting.
It does, yeah. But above I was responding to a commenter describing the voters as criminals, which is an unfortunately common view.
In law there isn't something like 'oh it seems this legal precept means...'
All legal precepts have carefully chosen words and a spirit in which they're based.
That's why is illegal a election for secession with only a part of the Spanish census.