Why wasn't there an option to help him find another role that he is better suited to?

I've managed poor performers before, if the performance is lacking because of attitude not skill, then performance management plans can be effective in telling the person to pick their game up, if they don't, then firing for this reason is acceptable.

However, if they are not suited to the role, and the blame for this sits squarely on the Employers shoulders for failing to properly assess the candidate, then the Employer should take responsibility for their stuff up in hiring this person in the first place, and look to help the person into a role more suitable, even if this is at another company. I've inherited two poor performers that I did this for. They shouldn't have been hired in the first place. Now, because the hiring manager made a bad judgement call should we be firing these people and throwing them out on the street without an income? No, treat people like they are people first and foremost (they had families and financial responsibilities that come with it), recognise where the fault occurred, and move to rectify the cause. This is leadership.

Firing someone in the example given is a cowardly/weak manager's way of doing things.