I would answer maybe but probably not (and provide another numbered list).

(1) I don't really know where the salary-reporting websites get their figures, but I have to imagine it is net salary rather than gross salary. Net salary would already have deducted the cost of medical malpractice insurance so the numerical comparisons have already accounted for that. The reason I think that a net reporting is likely is because of how doctors' salaries would be passed to them. If they are paid by the hospital, then they don't pay medical malpractice directly. If they are a partnership, I would imagine medical malpractice is paid as a normal expense (same as nurses salaries, office rent, etc.) before money is distributed to the partners. I could be wrong.

(2) Even if those salaries are gross salaries AND medical malpractice rates are huge, US doctors still make a lot more. Even if cardiologists pay $150,000 more in medical malpractice, they would be doubling the UK salaries. ($250,000 vs. $120,000)

(3) I am not convinced medical malpractice insurance is really that costly (see link). The real cost seems to be in the increased cost of defensive medicine. But I am not a doctor so I really don't know.