This is bizzare advice. The author is confused by the meaning of “be yourself”.
“This above all: to thine own self be true, And it must follow, as the night the day, Thou canst not then be false to any man”
Being true to yourself means not affronting your conscience. Be true to your sense of honor and morality.
It does not mean you need to trumpet your every thought or whim. Being yourself does not ean you cannot honor your commitments, indeed it means you must. By accepting employment you agree to prioritize the business’s goals and work to best achieve them. In most cases this involves working harmoniously with others. Your priorities are to honor that commitment not to assert your personal ideas or opinions. If keeping your commitment to the business is not compatible with being true to your moral code you must resign.
does not ean = does not mean