Someone else might be able to chime in more specifically, but the ALF are a decentralized and militant animal liberation group that is known to participate in direct action. They’ve been labeled a terrorist group for their actions against animal agriculture. One thing they’ve done is free beagles (and other animals) from animal testing labs, as beagles are very obedient dogs and are tolerant of higher levels of abuse, so are frequently experimented on. I’m assuming the banner is one specific time they did that.
One of my old university professors is vegan and he liked to tell a story about how his child pointed out cows while they were driving. So they stopped and pet them through the fence on the side of a slow highway. Ranchers don’t want you to know this, but you can absolutely just stop and pet the cows and maybe be the only person in their life to show them genuine compassion.