You are right. If a user has any doubts, he should first carefully read the ToS page or contact support. However, I think one of the reasons why some users take the risk and use VPNs is that ISPs in some countries may restrict access to gambling sites. Therefore, a VPN may be a necessity for some users rather than their desire to break the rules of gambling sites.
By the way, here is the Duelbits rule regarding the use of VPNs:
Yeah, there are country that is not banned by Duelbits but cannot access some game provider. In order to access them they need to use VPN. Like for example, Philippines is not on a banned region but we cannot access Pragmatic Play and other slots. Pragmatic Play has offer lots of good slots game and is worth playing. In order for us to access those games we have to use VPN and set our VPN to different country's IP address.
I believe this kind of action is not breaking the rule stated on the ToS.