Blobs are self-contained plasma weapons, which may actually be possible, but projecting an incredibly long magnetic field out into space to contain a thin stream of high-energy plasma would have effects regardless of how heavily shielded your electronics are.
That would explain the subsystem damage, especially from slashing beams, although 300 years in the future I doubt electronics like what we have today will still be in use, let alone the protection mechanisms we use. However it is very heavily implied that the beams we see are plasma, the fact that we can see it at all shows it isn't just a laser.
