Thats true for most cameras where its a single DIGIC chip, but the 7D is pretty different with its dual DIGIC 4 setup, and a real alpha in my view.
The problem with ml on the 7d was to get it to start at all, and now they managed to find a way, but afaik just like on single digic cameras ml is only using/running on one cpu, so it's not like the whole thing needs to get rewritten.
If ml used to brick cameras it was mostly because invalid values were written to the Canon fw, the result was that the cameras refuses to respond until you de-brick it with a special mini-firmware. But nowadays ml reverse engineering has a very good idea what valid values are and they check them before setting them, so the main risk is contained no matter how many cpus are on the pcb.
Alpha doesn't have to = bricking risk, but there probably is a greater risk of bricking with the 7d compared to the other cameras, if not massive. The main limitations is that some functions aren't single digic only, so it needs extra work to get some things going, but isn't a particularly high priority camera to merit the extra effort, hence its ongoing alpha status compared to 5d cameras.
Also the firmware doesn't boot in the same way, and to get auto boot going is a much more laborious and in my view higher risk process. So any new features go on top of those again.