In reading the other answers, it seems to me that they try to skirt around the issue and circumvent the actual question by saying something like:
"Resources" refers to more than just people, and the context of your situation is ambiguous (meaning your manager's response can be interpreted liberally, in a "non-offensive" way)
This is missing the point entirely, in my opinion. Because you are a resource.
It's very likely that your manager was referring to people as "resources". This is very, very common in corporate settings. I hear people referred to as "resources" every single day in my office. We often say things like:
- "How many offshore resources do we have working on this project?"
- "We don't have enough developer resources to meet this deadline."
It's not meant to be offensive. You take it to be dehumanizing, as treating you like an object. And in a sense, you are correct. In a large business, people simply are things, each of which has a function (your job), a price (your salary), and a value (how much you add to the company). To people like Senior Vice Presidents, workers are assets, exactly the same as the office in which you work, the equipment you use, and the product you produce/sell.
You may not like the fact that you boil down to just another number in someone's figures, at the end of the day, but that's the truth of the matter.
But there's no need to be offended by this! There is absolutely no negative connotation in a manager calling the people he manages "resources". My manager refers to me as a resource to other business people, and we have an excellent relationship, both professionally and personally. This issue is in your mindset, not in your manager. You are taking insult to something where no insult is intended or even present.
Instead, focus on what your manager is actually saying:
At the moment I don't have any resource available for completing this assignment.
If you look past the supposed slight, you'll see that he is actually protecting you from the other manager. He is protecting you from having to put in overtime or from becoming overworked in order to meet this other manager's demand and whatever his deadline is. And that's a good thing. It means your manager is putting his project and his people first.
If you don't like your manager, or if he treats employees in a poor manner, that's something different, and it's a product of his character. But his usage of the word "resources" has absolutely no bearing on that, and he uses it appropriately for a business setting.