The friend is overreacting to a common practice. The plates are thoroughly cleaned in a dishwasher, ensuring they are sanitized. It's unfair to question someone's entire kitchen hygiene based on one incident. The host's feelings are valid, as trust in their cooking has been unfairly undermined.
Letting a dog lick a plate that a human eats from is indeed a questionable practice, regardless of subsequent dishwashing. The friend's reaction is understandable, as hygiene standards are subjective and personal. The host is being overly sensitive; the friend simply expressed discomfort and concern about potential contamination.
While the host's cleaning methods might be adequate, the friend is entitled to their own standards of cleanliness and hygiene. The host's actions, while not inherently dangerous, could reasonably be perceived as unsanitary by others. Therefore, the friend's reaction, though strong, is not entirely unwarranted, but they should have communicated their concerns more respectfully. It is crucial to respect each other's boundaries and communicate concerns effectively without resorting to accusatory statements.