The copying of DVDs or ripping of DVD movies is illegal in the US. The DMCA prohibits it in the US. Handbrake is from a French company I believe. Many DVD ripping programs exist but they're not sold in the US, except on the Internet.
Go read about the DMCA for more information about US laws. Different countries have different laws regarding this. Most countries have no such laws (although many do like EU) and people make copies of DVDs and sell them for a profit, rip DVDs to data files and distribute them on the Internet, and etc.
I think the point of the DMCA is for people to not make copies and sell them, as the DMCA was designed to prohibit the copying/ripping of this video content in the first place so it didn't end up being sold via hard copy or distributed for free over the Internet via digital files. One would think that if he/she owns a DVD he or she should be able to rip it to their computer for personal use, however, according to the DMCA one would be wrong to think that.
