https://spencerfernando.com/2019/10/19/read-warren-kinsella-issues-statement/

Here he explicitly calls him a racist and anti-Semite:

I’ve been researching, writing about, and opposing racism for more than three decades. Maxime Bernier and his People’s Party are indisputably racist. They are bigots. They have anti-Semitic and homophobic members.

In this particular context, it is because Bernier hired someone Kinsella had fired for theft and anti-semetic views.

I haven’t been able to find the original statement of claim. I can’t seem to be able to find the original sources that were cited in it either, such as: http://warrenkinsella.com/2019/02/is-maxime-bernier-a-racist/

Not the best source, but one of the only ones that has any sorts of quotes: https://tnc.news/2019/12/11/maxime-bernier-demands-retraction-and-apology-in-defamation-notice-to-warren-kinsella/

”Is it necessary, at the end of all this, to label Maxime Bernier a racist? Do we really need to prove that he is a telegenic bigot who panders to the worst in people?” writes Kinsella in the blog post.

“No. By his words, and by his deeds, we all know who Maxime Bernier is.”

Personally, I believe someone can be opposed to immigration without being a racist, and be opposed to multiculturalism without being a racist. There are protectionist arguments for being against immigration, and one can desire a multiracial but mono cultural society. Or at least a multicultural society that holds shared values (perhaps Bernier has an opposition to how some faiths don’t believe that women deserve the same rights as men, perhaps that’s what he means by “extreme multiculturalism”. Is that racist?)