Well, there's two very different views of reality.. And one of them appears to be from a very unhappy customer.
Is it possible that different IBM Depts - or IBM regions, are selling Redhat Software/Support without much actual involvement of the Redhat business? Like the might have done in their traditional reseller/consulting/support role?
TBH I actually think it's likely - sales and account execs can probably just tickbox add RH stuff to their package deals, copy&paste the slide deck - and post sale the customer support channel will be the general enterprise support one.
IBM are probably very deliberately channelling all first level support through there anyway, same as for everything else - so core Redhat support staff might only get looped in for 2nd and 3rd level issues for those accounts, if at all.
It's quite easy to see that effectively creating two sales/support channels depending on whether you "bought from Redhat" or "packaged from IBM" - but equally it's unlikely to be presented or perceived that way, until it's too late.
I believe you when you say they've been hands off - it's surprising, but I can also see how it would make this kind of situation _worse_, because they're still effectively treating redhat as an "external" provider they resell.
Not that fully integrating the business would make it better of course, probably just different worse ( just based on my experience of corporate mergers, not IBM specific... ).