What a lot of us will do is say "see, look how good this is!!" Then, the foot comes off the gas pedal, and we celebrate all the success we totally did getting this passed.
I do have something to say to this.
Who are these "a lot of us?" I think it's important to be specific about who we're talking about here when we make these claims. Where's the historical precedence for this idea that another federal holiday is going to make Black people take the foot off the gas pedal?
Because most Black people I know, especially those who are active in the work of Black liberation, aren't that easily distracted.
And that's really just, unintentionally and in my opinion, contributing to the dehumanization of Black people in its own way. It refuses to engage with what Black people actually think and perpetuates this idea that Black people are incapable of walking and chewing gum at the same time. Regardless of how anybody feels about the significance of Juneteenth being recognized as a federal holiday, I find it difficult (based on my own lived experience) to buy into this idea that this is going to meaningfully change anything in terms of Black activism. Specifically,
who are these people who would have been activated for the cause tomorrow, next week, or next month, but who now won't be because...Juneteenth?
If Juneteenth is enough to make you disengage, I question how engaged you were to start with.
EDIT: I realize on second read of your post that you were probably talking specifically about white people here? But a lot of what I said still stands to that.