Neither Dirty Harry nor Walking Tall is a true vigilante movie. Each of the protagonists is an authorized law enforcement officer.
A vigilante, as such, takes the law into his own hands--no authorization or affirmation by the regulating powers.
If anything, the above mentioned two are views that while the system has problems in dealing with known and obvious criminals it has a reluctance or impotence to issue reasonable punishment because it is confined by its own language and bureaucracy.
The simple but clear minded minded protagonists produce the corrective for felons. In Harry's case, no further consequences are known to the audience while in Buford's he suffers the ultimate price for exacting justice.
These movies are not vigilante movies, rather benedictions of cops acting on their own initiatives--which are apparently just but encourage the notion that police, as we see so often, as justified no matter what they decide or how much force is applied. ( See the 2nd of the Dirty Harry movies Magnum Force which supports this.)
No vigilantes here, just cops--corrupt cops-- as also protrayed in Prince of the City, Serpico, Romeo is Bleeding, The Bad Lieutenant, The Professional.
The real vigilantes in film are shown in the likes of Shane, Ride the High Country.