I've seen many banks that have legacy systems what ONLY work in IE6, so they can't upgrade until they apps are re-written, but those apps are so big they don't want to touch it or they have some longer term project to replace this, blah blah. Some crap littered with ActiveX plugins no doubt. I know HSBC have (what appears to me anyway) to be like this.
But yes, agree the work/personal related thing, they can easily buy at home and if the workplace has such an antiquated attitude to these things then they probably also have your internet access to watch and lock down anyway.
So then the IT department chose for them not to be able to use a certain online shop. If the online shopping is work-related, then it's the IT department's job to facilitate this and upgrade the systems. If the online shopping is not work-related, you have the option to do it in your own time, with your own browser on your own PC--the same situation as people that do not spend their working hours surfing the web (because they might not have office jobs).
To expand on my argument, if you have to use IE6 or IE7 because your company says you have to, then that's a restriction you have to live with while at work. It's akin to someone complaining that they can't stop off for personal shopping while they're on the clock and being paid mileage.
You're free to do whatever you want on your own personal time. You don't have to shop online while you're at work (and it's a huge security risk to do so), so complaining that it's inconvenient doesn't really fly.