He is right a bit maybe but for the very end 'we do not do that to you', the Thais do all kinds of stuff in other countries in terms of business, corruption and bribes. It's always these Thais who then do like foreigners, because they likely studied abroad or whatever, who speak like if Thailand is some fairytale.
To say Thais can do bribes and corruption, but you as a foreigner should not, is obviously stupid to say as well. You can't live a easy life in a country where corruption thrives, without joining the corruption sometimes, specially if you live in certain areas or you would do business in perhaps hospitality and tourism.
When in Rome, do as the Romans do. If he wants foreigners to not do it, start with addressing the locals their actions and behavior instead of the 0.0001% incidents caused by foreigners here.