An electro magnetic event (man-made or natural) that is sufficiently powerful enough to corrupt magnetically stored data is also more than likely going to be sufficiently powerful to really mess with everything that relies on microprocessors to work.
There has been some proposals around requiring the electric industry to harden their infrastructure and systems to deal with this type of event. Assume the utilities do manage to somehow fund this type of hardening (which would be a massive undertaking in both time and expense). You still need to ask yourself what is going to be left to consume this power. The event is likely to leave many if not most things inoperable on a very wide scale. This means cell phones, computers, televisions, air conditioners, refrigerators, stoves. Any car made after around 1980 is probably also a non-starter. So there's power available, but not much left to consume it. Even if you have protected your data and your data center and have power, what percentage of companies have not?
This would be a hugely disruptive event that would take massive effort and years to recover from for any modern society. Maybe when the dust settles it might be nice to know what you have in your 401(k) and how much back taxes you owe; but then again it's equally possible that all this stuff will be irrelevant in the "new normal."
I agree that this is not an "extinction event" but it could very easily be sufficient to significantly change the political and societal landscape.