“Goes” and “may” are both present participle, whereas “went” is simple past participle. To match “went”, one would have to use the word “might” (simple past participle of “may”). The choice of the word “might”, however, is inappropriate in this context because the headline is referring to something that would happen in the future (and is less than certain to), and the word “might” typically refers to things that could have happened in the past. “May” refers to things that are likely to happen in the present or future, making it the appropriate word choice.

Edit: the verb tenses should match because the first clause is a dependent clause which depends on the second clause which defines the subject “Humane”. If the first clause had been an independent clause, then it would be OK for the verb tenses not to match. Bad style, but not grammatically incorrect.