That flag is to honor police officers, especially those that have fallen in the line of duty. So that person very may have well just vandalized someone's way of honoring somebody they loved and lost. This post makes me very sad.
*edit: see my response under all of guest_ comments*
The flag is not inherently anti anything, but it is also not originated or primarily a symbol of fallen protectors. There is a lot of controversy around the symbol, which has existed over 50 or so years but changed meanings and affiliations before its most recent comeback. The flag at its core represents a blue line (usually a police or military force), separating the symbol of those they protect from a symbol of danger or chaos.
It was picked up as a symbol of the “blue lives matter” reactionary movement that popped up in response to the “black lives matter” movement and thusly currently carries controversy as pertaining to topical issues of race. It also carries controversy as many see and have seen it as a decisive symbol that is also associated with certain other ideas that are counter to the mission statement of public servants.
The symbol also was used a few decades back to represent the blue wall of silence- the code that police officers keep rank with each other and not report misconduct or any potentially damaging information outside of themselves.
As other responses here show, like any symbol, this symbol can mean different things to different people and isn’t inherently a symbol of hate- but many departments ban its display because of its many meanings making it insensitive and possibly inflammatory. Symbols take meaning in use and in how we see them. Some people think the actual US flag is a symbol of hate, tyranny, etc. some people (I once met an old Latvian woman who was a WW2 refugee from the Russians to Germany who felt this way-) see the Nazi Swastika as a symbol of hope and freedom. It’s all relative.
What is NOT relative however is that people do not have a right to destroy or deface the property of others or to violate their freedom of speech simply because they do not like the message. It is NOT relative that even if this person bought that sticker themselves and did this to their property that it is insensitive and inflammatory to deface symbols that other people believe in. Defacing a “thin blue line flag” just makes a person guilty of all the bad things that many believe the flag stands for, and only feeds the division and “us vs them” the flag is accused of creating.
I speak to from personal experience. I've had a close family member die while on duty and these are the exact flags that they give you and that most surviving family members display. I know it has been this way for at least 8 years, and I am sure much longer than that. I never said it was the ONLY thing the flag meant, and I know it has been more controversial because of everything that's happened in the past year. But of the people I know that have this on their car, they all do so to commemorate somebody they loved and lost. And I know anyone in my family would be deeply hurt to see it defaced like this.
@changetheworld- I am sorry for the loss of who I will assume was a fine, and at least dear human being to you and many others. I certainly agree with you that to deface such a flag- or really almost any personal property of another wether it just be for sick giggles or some political idea is wrong. I am not, nor was I saying that this flag stands for those things. But in reference to the original question of wether the flag is anti lgbtq+ or not- and the implied question of why one might be motivated to deface it, the answers given were incomplete.
As you say, in your experience these flags mean one thing. And from your experience that is true. However there are other perspectives on what they mean- and those cannot be left out if the meaning of the symbol is being discussed. Symbols are tough things to deal with. Their meanings and context can vary or even chance with time- the confederate flag is one such flag which many argue is a symbol of hate and many others argue that it is not, but has different and powerful meaning. I’m not here to render a judgment on this flag not a universal ruling on how to handle symbols that some see as problematic. Just answering a question as honestly and comprehensively as I am able.
*edit: see my response under all of guest_ comments*
I dunno, maybe not touch what isn't yours? Is that too far out?