The Do Not Call Registry relies on telemarketers to follow the law and respect the list. Legitimate telemarketers should respect this list because the penalties for violating it are steep.
Some automated phone dialers are legally used by marketing companies, but most are "robocalls" which are operated by illegal actors.
Unfortunately, Robocallers, Caller ID Spoofers and other illegal callers do not respect the Do Not call list. However the FCC is working with the voice industry to try to reduce the ability for them to successfully imitate numbers other than their own. Click here for more Information on the FCC's STIR/SHAKEN Caller ID verification work