I'm the founder of ShareCG and I feel your frustration, understand where you're coming from and want to humanize the responses from our moderators.  Here's the interface our moderators use when approving or rejecting each upload:

From your comment it appears that they are taking the easy way out by simply checking one of the reasons without providing a personalized explanatory note.  This sends the user an automatically formatted message that just says, for example, "Your xxx model was rejected for technical issues," without going into any detail.  Because you've brought this to my attention I've instituted a new policy requiring moderators to explain in human English with detail why an upload is rejected. 

An email link is also included in this message so you can respond and converse with the moderator if you disagree or have a point to make etc.

You're right, automated messages without the human touch can be off putting and I feel that this change in policy will improve your experience.

Please feel free to correspond with me directly - david.heller (at) sharecg.com. 

I really appreciate your input since it's already made a difference that will benefit all our members.