Q: Quantum physics is an esoteric theory, that nobody understands and that cannot be tested.
A: Quantum physics may seem counterintuitive at first when putting into words, but when expressed in the language of mathematics it is very clear. Countless predictions from quantum physics have been tested and turned out to be true.
Q: Quantum computers will never work. because it is impossible to make precise enough hardware.
A: Fortunately, quantum computer hardware does not need to be infinitely precise - when a (challenging) level of precision is reached, quantum error correction keeps the computer going.
Q: The goals of quantum computing are not ambitious enough, because quantum computers with more than 2000 qubits already exist.
A: These large machines follow the paradigm of quantum annealing, which is interesting, but cannot be compared on equal footing to standard quantum computers.