Certainly the only people upset about tear gas at the border are those who were outraged when it was used monthly under Obama, as this is just a continuation of the Obama policy. Link and excerpts from source CW for length
Obama administration used tear gas at border once a month
The same tear gas agent that the Trump administration is taking heat for deploying against a border mob this weekend is actually used fairly frequently — including more than once a month during some years under President Obama, according to Homeland Security data.
“The facts are, the policy written under President Obama allows us to use tear gas to disperse a crowd that was very dangerous,” he told the network.
https://m.washingtontimes.com/news/2018/nov/26/obama-administration-used-tear-gas-border-once-mon/
So yet again we have outrage at Trump for doing what Obama did. I don't know that you're seeing things clearly if things are always okay for "us" to do but bad for "them" to do.
