Claimbulking is form of loaded language that consists in indiscriminately referring to every unorthodox statement as a "claim", with no distinction between mere claims and other forms of statements such as observations, deductions, hypothesis, theories, quotes, etc..
It's commonly used as a rhetorical weapon to delegitimize inconvenient ideas, since by conflating merely speculative statements (such as hypothesis and theories) with conclusive ones ("claims") it presents opponents' positions as being more radical and/or arbitrary than they actually are.
It also carries a hidden ideological purpose, specifically that of delegitimizing rational debate: because claims (different from other kind of statements) cannot be ascertained by mere logic/rational means, but only through direct evidence and source credibility, treating everything as a "claim" implicitly removes any rational consideration away from the equation, reducing the entirety of human knowledge to a mere issue of sources and authority.