I agree to some degree and I regularly reject a lot of suggested edits..... However you should note that just because its a 'minor' edit doesn't necessary mean that it should be rejected.
Here's my stance on what I believe:
For example if an appropriate tag has been added to a question but the question could be improved some what via spelling, grammar or anything else that you feel you should add then ideally if you should click the improve button... I would hope that people who don't have the time to improve the question or answer simply press the skip button rather than just rejecting it... It doesn't necessary indicate that the user who has proposed the edit is lazy but rather you may have better English skills or more understanding about how stack exchange works and want the user base wants from it.
Minors Still Contribute to User Experience and overtime Administration
If you believe a question has a minor edit such as a tag then by no means should you reject that edit if an appropriate tag has been added, after all the edit is still valid, and as I said if it can't be improved then why reject?
People have better Grammar and Spelling than others
Another thing is that if a person has given an edit a go but you feel the grammar or spelling can still be improved or the answer/question can be made even more clear then again it doesn't necessary mean its an invalid edit, questions and answers often go though dozens of edits before they become excellent to perfect, this is the beauty of the Stack Exchange Q&A software.
Not Defending Minor Editors
By no means am I defending people who blatantly know that the question or answer can be improved more than their minor edit but wish to raise the above points to not categorize
ALL PEOPLE who do
helpful minor edits as being lazy.