When you are running a business I think it makes sense not to link to other accounts that have negative comments about your business. Customers click on the links.
I'm not excusing her original comments in any way. I just think that the blocking may be part of the damage control plan, possibly recommended by her PR team (if she has one now).
I don't know though. I am not an instagram user. I only peeked on OP's profile to see the comment stream. And I clicked on one of the commenters to see what came up.
I really don't think the instagram blocking is personal. I think it was a business decision.
FWIW, (again, NOT excusing,) the artists I have worked with in the past expressed lots of concerns about putting pictures of their works online for fear that they would be copied. Their work is very personal to them. You would think someone who marketed to the general public on this scale would get over the control issues by now, but I do understand the desire to control how their works are used. You would have to maintain a relatively low profile to make that happen, though.
Just another POV. Outbursts are not acceptable regardless. I learned that back when email was the primary mode of electronic communication.