That is your browser. Hassaan, you should add autocomplete="name" to prevent this in the future since clearly it scares some folks. He didn't do anything that its just your browser looking for autocomplete text boxes.
If I count this correctly, the damage is 0.9 £ per person per month. So this is what the claimant thinks should be an average and fair monthly compensation for being a FB user for that time.
Meanwhile, Facebook's ARPU in Europe is ~$50/user/year [1], so they're roughly $40 ahead per claimant after this lawsuit. Just a cost of doing business...
Revenue is not the same as profit, from the source you quoted the ARPU in Europe for 2016 (period lawsuit starts) is half of what it is in 2020, also it's closer to 15$ since GBP is worth more than USD.
Highly doubt this would be in the "cost of doing business category"