No, that is being aggressive, It is all in the eye of the beholder. If the manager is encouraging aggressive base running things like that will happen more often than if he did not encourage it. How do you determine objectively the stupidity of being aggressive on the bases?
If players don't cover or back up bases, if they don't hit the cut-off man, if they forget how many outs there are, if they try to make a play when they shouldn't; these are things that can be considered mistakes or lack of fundamentals. Running aggressively when the manager wants you to is not a mistake unless the manager tells you it is and your behavior should change after he tells you.