Ok, you want specifics.
1) Valve did deliver a version of Steam which did, in fact, wipe hard drives of considerable amounts of data. I was curious about that one and did check into why or how it could happen and found it. If they can deliver a program once, which can do significant damage to a system there is nothing to say it cannot happen again.
2) They lost thier source code to Half Life once. It was poor practices which lead to it. This suggests they do not have a strong desire to allow a network admin to do the right things to secure thier network. They purportedly fixed it, but it took a disaster to make it happen. In my experience, when a company flagrantly ignores very basic security, it will funnel its way into the very code they provide.
Statistically, I will not allow them the chance to provide a piece of software which could in fact create a security issue.
Those two reasons alone are enough to keep me away from it. Regardless of who runs it without issue today, does not mean there will never be an issue. The problems with the issues they can have are not worth the risk to me.
Risk assessment is part of my job and has been a part of my career for over 20 years. I take it very seriously.
There is nothing any user can say which will alter the risk assessment. Your opinions are just that. They are void of any risk assessment value. In this matter, the company providing the software is at the heart of the risk assessment. Thier history suggests they should not be trusted.
Viking obviously has done risk assessment and taken what he feels is appropriate measures to insure a stable network. While I am not saying this cannot be accomplished, I am also saying there are elements which you cannot control in this particular scenario. Knowing that and assessing the risk is up to the user.
There is not a game made which will ever be worth exposing my networks to the risks inherent with Steam. The risks are valid and proven.
