I hesitate to say that PETA's use of imagery goes too far. The videos and snapshots are available on their website for the viewer or interested party to peruse as they decide. Images are not being forced on an unassuming public.
It's apparent that PETA wants to shock. Their audience is probably made up of people with varying levels of knowledge and opinion on animal abuse and use. Perhaps by using graphic imagery they seek to incite a reaction and garner the attention of even the most passive viewers. Some images scream 'how can you not care about this, how can you avert your eyes, how can you disregard this animal treatment?'
However, I think that if an organization is going to make claims sometimes slanderous to other organizations, businesses and especially to individuals, some history and context of the images are in order. Did PETA members or employees take the pictures?
The graphics used and developed by PETA sometimes broach the same shock factor. For example, the well-known Olympic rings drip with blood as a corresponding colored figure stands in mid-hack above the logo, a cowering seal before this figure, its face turned up in innocent surprise. But further reading into the actual campaign to stop the slaughter of seals reveals the Olympics have nothing more to do with the inhumane practice than, in 2010, sharing a geographical location. On first glance, however, and without reading into the issue, the graphic comes across as equating the blame for seal slaughter with the Olympic committee.
This sort of leading imagery could delegitimize PETA's efforts to convince people their cause is true and worthy. Looking at an image like the one just discussed and forming a quick opinion, only to read deeper and find the original message is false, could frustrate people into distrust.