Well, I doubt you'll find any peer reviewed studies about the use of semantic overload, but there's a number of public polls and organizational mission statements that can be reviewed.
For instance, the HRC is one of the orgs that sells that kind of merch.
What are their stances on the various LGBTQ issues? Any wiggle room for a balanced discussion with the folks at the HRC on matters of affirming care for minors, or the sports topic?
How about the pro-choice advocacy groups that leverage the "women's rights are human rights" tagline and symbol? Are those groups open to any sort of balanced European-style solution, where there are allowances for the 3 exception scenarios, but the elective ones get capped somewhere around 15-16 weeks? Or are the heels pretty much dug in on the whole "on-demand/no limits" approach?
I've already provided screenshots from BLM DC showing their missions that go beyond "protecting black lives from police brutality"
Here's what the leader of the LA chapter had to say:
Black Lives Matter organizers are calling on shoppers to "resist white capitalism" this holiday season.
www.newsweek.com
"We say 'white capitalism' because it's important that we understand that the economic system and the racial structures are connected," said Abdullah during her weekly radio show, Beautiful Struggle. "We have to not only disrupt the systems of policing that literally kill our people, but we have to disrupt the white supremacist, capitalistic, patriarchal, heteronormative system that is really the root cause of these police killings."
Seems like there's a lot of other stuff being bundled in with "Black Live Matter" that go well beyond the simple semantic definition of that phrase, correct? So in order to "truly oppose the police killings of black people", we have to hop on board with disrupting capitalism, the patriarchy, and heteronormative systems?
The original official BLM "who we are" page (which they ended up removing after some backlash) mentioned "seek to dismantle the western-prescribed nuclear family unit"
A lot of that stuff has absolutely nothing to do with protecting black lives from police killings, several westernized countries have managed to address that issue (or never had much of an issue with that in the first place) without having to embrace any of the extraneous left-wing ideological baggage.
So, someone appealing to the more generic concept of "rejecting hate", and then attaching the slogans/symbols from movements that clearly have a much mor expansive lists of demands as the "buy-in", is overloading that phrase.
That's no different than if someone puts a sign out there saying "Defend freedom" (a concept that in the abstract sense, everyone would claim to agree with) and then cluttered up the sign with a bunch of pro-gun & anti-tax symbols and slogans, they're making a statement about what they think is involved with a person being considered "a true defender of freedom"