Quite so.
In the event of engine damage, you don't know exactly what has happened, or what substances, {smoke, fumes, fuel, engine oil, hydraulic fluid, extinguishing agent, CSD oil}, might have got into the bleed duct.
The last thing you want to do is incapacitate yourselves or your crew and passengers, with smoke or fumes, which would compound what started as a bad day into a disastrous one !
Don't use the affected bleed duct(s) in such a situation, If the left engine is affected, don't use the APU bleed either, because it shares part of the engine #1 pipework.