Cutting duplication and waste is fine, but that's not all that is happening here. The reduced competition resulting from approving this merger is already raising prices at the grocery store even though a key component (namely fuel prices) are falling.
There are also plenty of ways other than featherbedding to temper job losses, the Government Motors way, which does nobody any good. Moral companies provide outplacement services as just one example. They also make a reasonable attempt to place people internally where possible. They don't announce job cuts as it it is something to brag about to goose their stock price as clearly seems to be the case here.
If you RTFA, you'll see they plan to cut no production workers, just administrative workers...HR, payroll, accounting, etc. That's just more efficient.
I reject your premise, the French model of employment which obligates an employer for the life of the worker. These administrative types have skills which transfer easily. Jobs are available.