Public figures must be careful in word and deed, or they'll give people ammunition against them.
Tips
history
The phrase 口实 ('mouth-stuff', i.e. talking points) appears in 《尚书·仲虺之诰》: 于恐来世以台为口实 - fearing later generations would use 'me' as their talking point. By the Ming-Qing era 贻人口实 was a fixed idiom for handing critics ammunition.