Yes intrusive thoughts do not represent who we are, I think that the source of these thoughts is a negative energy stored inside our subconscious, as you said we must not ignore them but also we must not fight them and waste time and energy to get rid of them, so in my opinion the solution is to admit them and not to give them a great importance because they are just thoughts that come and go without causing real problems like clouds that fill the sky a moment and after it disappear, but to avoid this type of inconvenience it is better to practice important tips for our health (Sport, Meditation, deep breathing, good natural diet, good sleep, reading .. ..)