Weights are literally numbers computed as output. They are not instructions. The semantics of those numbers even when emplaced (loaded) in an artificial neural net is such that they do not execute. They are not instructions. LLM engines and diffusers perform searches where the weights are used to calculate additional output.
Is source code, like Python text, data? Yes. All code is data. But not all data are source code.
If I gave you a web request log, you would not assert it is a program. If I gave you a CSV file with time-series values from a sensor, you would not assert it is a program. If I hand you a database of contact information, you would not assert it is a program. Weight files are the equivalent of CSV files. They are are a dump of parameter values computed from training.
They are not a program.
The definition of computer program is well worn. So is the definition of source code, and the definition of parameters. Weights are parameters.