The figure in your linked page looks like it is based on data from a survey in which participant were asked which number they thought of when they heard the wor

The figure in your linked page looks like it is based on data from a survey in which participant were asked which number they thought of when they heard the word 'several'. Even if everyone taking the survey was aware that the word 'several' is inclusive of two, I'm not sure we would expect a different result. So, the results can't be used as evidence that anybody taking the survey did not think several is inclusive of two.