I moved your post to the vegetarian section
I'm vegan. I changed in the midst of my weight loss. I am happy I did. You can continue to do WW and be vegan.
Also, there is nothing that says you have to be vegan instantaneously. You can start removing animal products from your diet and increasing your plant based foods. Throughout my entire weight loss, I didn't eat much dairy at all and I didn't eat eggs very often so it wasn't difficult to cut those out. With meat, I started to increase my meatless meals and reduce my meat intake. One day, I just said "ok no more animal products" and that was that but it was already after I had reduced the amount of meat I was eating.