I don't have an idea about VPNs and Tor network. I thought they are used by hackers who do not want to be found. <…>
Not really. The vast amount of user are likely legit, and do it due to privacy concerns. Bear in mind that you connect to a ton of sites each day, and that IPs can be ultimately used to geolocate you. You don’t necessarily want sites to know where you are from.
In some instances, ISPs may be required to provide information on you (due to court orders where the procedure is respected, if not skipped by some direct government requirement in loose countries). I recall a case of torrent users receiving lawyer letters claiming a certain amount of money to avoid being sue for downloading episodes from a certain pay-per-view tv series. The layers went through court, and obtained data from ISPs for bags of given IPs. Granted that technically, the series should not have been downloaded, but even so. Now take this example a step further and assume other ungreateful examples that once could potentially device. The idea is to shield yourself, even if strictly because you are 100% legit type person (hey, who's not?), but want your privacy respected (i.e. not Facebook/Instagram type profiles).