The Buddha and Mahavira as rivals?

This article points out Buddhism negatively perceives Mahavira (Nigantha Nataputta). Similarly, Jainism negatively perceives the Buddha:
https://www.quora.com/What-is-the-difference-between-Gautama-Buddha-and-Mahavira

They did not meet one another. Mahavira was older than the Buddha: https://buddhism.stackexchange.com/questions/22639/did-buddha-ever-met-mahavirjain-god

This article is Mahavira and the Buddha: http://buddhism.lib.ntu.edu.tw/FULLTEXT/JR-ENG/keima.htm  

Compare 2 religions: https://www.diffen.com/difference/Buddhism_vs_Jainism

Compare another text: http://www.san.beck.org/GPJ3-Mahavira,Buddha.html  

Very bias that mahavira vomited with hot blood: https://palisuttas.wordpress.com/2015/11/01/upali-sutta-mn-56/

Vietnamese: https://www.budsas.org/uni/u-kinh-trungbo/trung56.htm