Now the real reason is that venezuela is a "hostile influence in the western hemisphere" both from a russia/china perspective as well as an energy security perspective so this was a matter of when not if (monroe doctrine and all that).
This is not the first time the US has intervened in LatAm, and it won't be the last. Being the sole influence in N and S america is a defining feature of america and all americans, and has been so since 1823.