Before you can use any GPL'ed piece of software, you have to agree to the terms of the GPL. (If you don't, you don't have the right to copy the software, under copyright law).
No, you're absolutely wrong. The person who made the copy FOR you had to agree to the GPL in order to copy the software. But there is absolutely nothing that you must agree to in order to use that copy that was distributed to you. At your option, you can reject the terms of the GPL, and you have the same copying rights that default copyright law gives you - the right to make one backup copy for personal use only.