Sounds like a problem with Chrome to me. Browsers (theoretically) are not supposed to crash. If some crazy script can cause them to access memory improperly and crash, that is bad.
It doesn't matter that the website is coded poorly, with that opinion, malicious websites are "coded poorly" as well. Now, it doesn't mean that the crash you see is necessarily a security vuln, but it is at least a bug.
I see this under Linux. Chrome (big C) doesn't crash, the tab hangs. The browser chrome (little C) is very responsive and the task manager functions as expected. This very well may still be a Chrome bug, but the process isolation works splendidly.
It doesn't matter that the website is coded poorly, with that opinion, malicious websites are "coded poorly" as well. Now, it doesn't mean that the crash you see is necessarily a security vuln, but it is at least a bug.