The difference here is the balance between /average user/ needs and possibilities of abuse.
Shell access on DH isn't as abused as you might think it. DH servers are actually very secure on the command line. I've used plenty of other web hosts that turn off shell cause of the abuse. And others I've been on where their severs were very unsecure with HIGH possibility of above. One of them I was able to access the user/pass of their entire customer base.
DH folks know what they are doing. I do appreciate the security of their servers. This is one reason WHY I've kept with them for so long. They know their s*. The only things that get hacked when things DO get hacked are customer sites....and those are things DH has no control over. Users don't know the security of their own scripts and the holes to get abused, but they often only effect their person sites (and often server loads, too).
Everything has potential of abuse, this is correct. However, the DH customer base must prove to DH that any new feature is in high enough demand to take that risk.
For example of a risk that's been shut off soon is the email thing. User catch-all is forwarding over to much stuff to AOL and other servers that AOL is blocking DH. NOW the risk is greater than the demand and DH is making changes to remove the risk.
So, like I said above, vote for the feature. If it gets enough votes, DH folks will decide if they want to take on the risks for the good of their customers.
yerba# rm -rf /etc