I can't comment about IAR, having never used their products (other than their free AVR assembler many years ago). It could well be that IAR have very good support - I've heard nothing to the contrary. Certainly most commercial suppliers who hope to stay in business for a long time will put a lot of effort into their support.
But I know from personal experience that not all commercial suppliers have good support. And some will require a lot of effort to reach that support - perhaps you have to fill out detailed web forms listing exact versions of all the software you are using, or maybe you have to fight past layer 1 support staff mindlessly telling you to update to the latest version, or try rebooting your computer, or maybe the company's support telephone hours don't match your timezone.
And in some cases, people simply prefer the more informal atmosphere of a newsgroup, web forum or other discussion forum with other users.
I'm not saying it is not a good idea for the OP to ask IAR's technical support - just that sometimes people have good reason for posing questions here rather than asking support first.