I have been a scientist for more than 40 years, having studied at Cambridge and Harvard. I researched and taught at Cambridge University, was a research fellow of the Royal Society, and have more than 80 publications in peer-reviewed journals. I am strongly pro-science.
The label of 'marathoner' has, from the beginning, been awarded to those who went the distance under their own power, whether they ran, walked, crawled or tiptoed. When you cross that finish line, you've entered an elite group. About one-tenth of one percent of the population has done it. Don't let anyone take that great achievement away from you.