Why Faith Kipyegon was disqualified despite finishing second in Paris Olympics 5000m final

"Kenya's Beatrice Chebet wins 5,000m gold, Faith Kipyegon's silver reinstated"
Kenya lost an Olympics silver medal after Faith Kipyegon was disqualified in the women’s 5,000m final on Monday night.
What was supposed to be a good day turned out worse for Kipyegon after losing gold to compatriot Beatrice Chebet in the final stretch before she later learnt that her second place would count for nothing as she was disqualified for jostling and obstruction.
The dreadful moment happed in the final 800m when Kipyegon did not take kindly to Gudaf Tsegay’s tactics to box her in and had a go at her, raising her arm in anger before she continued her race.