[krupan]

Using software is not the same as copying the code. Copyright law only covers making and distributing copies of things. It's a subtlety of the law.

By default (in the US) you are not permitted to copy someone else's work (with some exceptions for "fair use") without the copyright holders permission.

Software copyright holders generally give you a copy of their software only if you agree with their terms (it's a contract agreement, or license. Their terms usually bind you to not use the software in certain ways and to not make any copies of the copy you have been given. If you break that contract then you have no permission to have a copy of the software and you are in violation of copyright law.

None of the Open Source licenses restrict how you use the software. If you create your own license that does restrict use then by definition it is not an Open Source license. Open Source licenses do put restrictions on copies you make and distribute (some licenses impose more restrictions than others).